Switch to nexus style mode completely v3

This is a 3rd iteration of the patch in which we go completely Nexus.
We eliminate external sdcard completely and use it as /data that can be fully encrypted.
In addition we perform series of storage layout changes, cleanups and optimizations.

Now to the details:
* Use original "userdata" parititon as /system (60% more space for GApps and ODEX data).
* Use original system partiton as /cache (one can relocate dalvik-cache here
  to allow apps ODEX data to not be encrypted and to be fetched faster).
  This also allow much faster boot with encrypted data (dalvik-cache is available on boot for asking user's password).
* Reduce size of primary zram swap to 96MB since profiling showed this to be sufficient (20% more RAM).
* Use original "cache" partition as secondary swap (to provide backup swap for smaller zram swap).
* We create pre-odexed build optimized for "small" devices which should allow the following:
  - Avoid usage of userdata for DEX data of system apps and data duplication
  - Avoid encryption of ODEX data of system apps
  - Allow much faster access from /system partition
  - Enable ART-small mode which pre-compiles ODEX data for system apps and relocaes to dalvik-cache only bare minimum of clasees
* Add misc recovery related settings and coresponding changes to TWRP in order to support above.
* Modify recovery related settings (this device tree can be used for building TWRP image)
* Remove duplicated default init.rc code
* General cleanups

Change-Id: Ieb2b58569fcc20bb2d77def3f205fd009386d7bc

BoardConfig.mk

@@ -194,7 +194,7 @@ TW_INCLUDE_NTFS_3G := true
 TW_BRIGHTNESS_PATH := "/sys/class/leds/lcd-backlight/brightness"
 TW_BACKUP_DATA_MEDIA := true
 
-# Dalvik/ART optimizations
+# Dalvik/ART
 WITH_DEXPREOPT := true
 WITH_DEXPREOPT_COMP := false
 WITH_DEXPREOPT_PIC := true

device_pyramid.mk

@@ -226,6 +226,7 @@ $(call inherit-product, device/htc/pyramid/media_a1026.mk)
 ## htc audio settings
 $(call inherit-product, device/htc/pyramid/media_htcaudio.mk)
 
+# setup dalvik vm configs
 $(call inherit-product, frameworks/native/build/phone-hdpi-512-dalvik-heap.mk)
 
 # Discard inherited values and use our own instead.

recovery/root/etc/twrp.fstab

@@ -4,6 +4,6 @@
 /recovery       emmc            /dev/block/mmcblk0p21
 /system         ext4            /dev/block/mmcblk0p23
 /data           f2fs            /dev/block/mmcblk1      length=-16384
-/cache          f2fs            /dev/block/mmcblk0p24
+/cache          ext4            /dev/block/mmcblk0p22
 /misc           emmc            /dev/block/mmcblk0p31
 /usbdisk        vfat            /dev/block/sda1         /dev/block/sda          flags=display="usbdisk";storage;wipeingui;removable

rootdir/etc/fstab.pyramid

@@ -9,16 +9,16 @@
 /dev/block/platform/msm_sdcc.1/by-name/misc        /misc              emmc        defaults                                                  defaults
 /dev/block/platform/msm_sdcc.1/by-name/devlog      /devlog            ext4        rw,noatime,nosuid,nodev,barrier=0                         wait
 /dev/block/platform/msm_sdcc.1/by-name/userdata    /system            ext4        ro,noatime,barrier=0                                      wait
-/dev/block/platform/msm_sdcc.1/by-name/cache       /cache             ext4        noatime,nosuid,nodev,barrier=1,data=ordered,nomblk_io_submit,noauto_da_alloc,errors=panic wait,check
-/dev/block/platform/msm_sdcc.1/by-name/cache       /cache             f2fs        rw,discard,nosuid,nodev,noatime,nodiratime,inline_xattr   wait,check
+/dev/block/platform/msm_sdcc.1/by-name/system      /cache             ext4        noatime,nosuid,nodev,barrier=1,data=ordered,nomblk_io_submit,noauto_da_alloc,errors=panic wait,check
+/dev/block/platform/msm_sdcc.1/by-name/system      /cache             f2fs        rw,discard,nosuid,nodev,noatime,nodiratime,inline_xattr   wait,check
 /dev/block/platform/msm_sdcc.3/mmcblk1             /data              ext4        noatime,nosuid,nodev,barrier=1,data=ordered,nomblk_io_submit,noauto_da_alloc,errors=panic wait,check,encryptable=footer,length=-16384
 /dev/block/platform/msm_sdcc.3/mmcblk1             /data              f2fs        noatime,nodiratime,nosuid,nodev,inline_xattr,discard,rw   wait,check,encryptable=footer,length=-16384
 
 # USB storage
 /devices/platform/msm_hsusb_host.0/usb1            auto               auto        defaults                                                  voldmanaged=usbdisk:auto,noemulatedsd
 
 # ZRAM
-/dev/block/zram0                                   none               swap        defaults                                                  zramsize=134217728
+/dev/block/zram0                                   none               swap        defaults                                                  zramsize=100663296
 
 # System as secondary swap
-/dev/block/platform/msm_sdcc.1/by-name/system      none               swap        defaults                                                  defaults
+/dev/block/platform/msm_sdcc.1/by-name/cache       none               swap        defaults                                                  defaults

system_prop.mk

@@ -24,8 +24,6 @@ PRODUCT_PROPERTY_OVERRIDES += \
 PRODUCT_PROPERTY_OVERRIDES += \
     windowsmgr.max_events_per_sec=300 \
     pm.sleep_mode=1
-#    dalvik.vm.dexopt-data-only=1 \
-#    dalvik.vm.dexopt-flags=m=y \
 
 # Display
 PRODUCT_PROPERTY_OVERRIDES += \
@@ -42,7 +40,6 @@ PRODUCT_PROPERTY_OVERRIDES += \
 PRODUCT_PROPERTY_OVERRIDES += \
     ro.setupwizard.enable_bypass=1 \
     ro.com.google.locationfeatures=1
-#    dalvik.vm.lockprof.threshold=500 \
 
 # USB-OTG
 persist.sys.isUsbOtgEnabled=true