Remove usage of Bsec helper class (#31)

This removes usage of the Bosch provided Bsec helper class and
instead interfaces more directly with the underlying library.
Most importantly this allows removal of the forced delay within
the component loop which was causing various problems within the
ESPHome ecosystem.

Unfortunately due to the added timing complexities this does mean
that I have removed support for reading from multiple sensors as it
would take considerable extra effort to appropriately manage the
bsec library state.

README.md

@@ -116,26 +116,6 @@ text_sensor:
       name: "BME680 IAQ Accuracy"
 ```
 
-## Multiple sensors
-By defining multiple platform instances it is possible to read from multiple sensors.
-```yaml
-bme680_bsec:
-  - id: bme680_one
-    address: 0x76
-  - id: bme680_two
-    address: 0x77
-
-sensor:
-  - platform: bme680_bsec
-    bme680_bsec_id: bme680_one
-    temperature:
-      name: "BME680 One Temperature"
-  - platform: bme680_bsec
-    bme680_bsec_id: bme680_two
-    temperature:
-      name: "BME680 Two Temperature"
-```
-
 ## Indoor Air Quality (IAQ) Measurement
 Indoor Air Quality measurements are expressed in the IAQ index scale with 25IAQ corresponding to typical good air and 250IAQ
 indicating typical polluted air after calibration.
@@ -151,4 +131,4 @@ of the following values:
 - `Calibrated`: BSEC calibrated successfully.
 
 Every `state_save_interval`, or as soon thereafter as full calibration is reached, the current algorithm state is saved to flash
-so that the process does not have to start from zero on device restart.
+so that the process does not have to start from zero on device restart.

bme680_bsec/__init__.py

@@ -6,7 +6,6 @@
 CODEOWNERS = ['@trvrnrth']
 DEPENDENCIES = ['i2c']
 AUTO_LOAD = ['sensor', 'text_sensor']
-MULTI_CONF = True
 
 CONF_BME680_BSEC_ID = 'bme680_bsec_id'
 CONF_TEMPERATURE_OFFSET = 'temperature_offset'