v0.2.16

PROST v0.2.16

Fix warning about regex patterns.

Add split option to makedb command that splits large protein databases into chunks.

• prost.py makedb -s 1000 input.fa output will split input.fa into 1000 proteins and create output_0.prdb, output_1.prdb so on and so forth.
• prost.py mergedbs output_* merged.prdb will merge smaller databases into one big database