v2.4.0-beta

Here are the changes included in this beta.

• Fixed an issue that would causes bowtie2 to crash with --no-1mm-upfront specified
• Modified bowtie2-build script to better handle of flags and positional parameters
• Migrated all python scripts to python3
• Added support for wildcards input files tobowtie2 wrapper script e.g.
  bowtie2 -x index -q *.fq as opposed to bowtie2 -x index -q 1.fq,2.fq,3.fq...
• Fixed an issue causing bowtie2 to incorrectly process read names see #265
• Added support for allowing presets to be overridden by more specific options e.g
  bowtie2 -x index --local --very-fast-local --L22 -q reads.fq will cause bowtie2 to use a seed length
  or 22 instead of a seed length of 25 that's configured for --very-fast-local preset.
• Modified SAM output for -k/-a so that supplementary alignments get assigned a MAPQ of 255
• Fixed an issue that somtimes causes bowtie2-build to not generate reverse index files
• Added preliminary support for ppc64le architectures with the help of SIMDE project see #271 for details.