Create align.py "convenience command" for quick one-step bwa index+map

This lets one quickly index some fasta file(s) and map a set of reads
to it.

As an example, this will output sam format alignments:

docker run -v ~/local_files:/data \
	quay.io/refgenomics/docker-bwa \
	align data/reference_genome.fa /data/reads.fa --sam

Or, a sorted + indexed bam file:
docker run -v ~/local_files:/data \
	quay.io/refgenomics/docker-bwa \
	align data/reference_genome.fa /data/reads.fa \
	--bam -out output.bam
Add a bats test for align.py