BWT iterators implemented
Generalized BWT iterators over the Suffix type. Fixed Readme install instructions.
Merge pull request #13 from kvark/iter

BWT iterators
Generalized DC over the Distance type
Implemented MTF reader/writer as a separate post-bwt module.
Cleaned up old MTF inside DC. Added MTF to the test app.
Merge pull request #14 from kvark/iter

Generalized BWT iterators over the Suffix type
Moved DC and MTF into BWT namespace
Merge pull request #15 from kvark/iter

Separate MTF module, reader/writer for it, and DC cleanup
if_ok => try
extra => test