v0.5.0-a4

Added

• encode_into and decode_into sans-io methods of Alphabet.
• Aligner class to handle alignment of a query to a database.
• ScoreMatrix.__eq__ implementation.
• Database.lengths property to get the lengths of all the sequences in a database without decoding them.
• pyopal.align top-level function to handle multithreaded alignments.

Fixed

• FullResult.cigar crashing on alignments starting with X.