Merge branch 'release/v2.1.1' into develop
Use SHARED flag for mmaped_file (read only memory mapping).
Added is_homopolymer method.
Added an interactive mode to the query subcommand.  Uses stdin to input mers.
Speed improvement to query sub-command.
Bumped version to 2.1.2.
Merge branch 'release/v2.1.2'