update readme.txt with romanize feature
renamed Readme.txt to Readme.MD for github happy
corrected name to README.md
Update README.md with features
more tweaks to sample songsw
moved todo into docs/
t due to readme edits on github Merge branch 'master' of github.com:nbogie/chord-transposer-haskell
Moved *.hs into src and updated cabal file
update gitignore with location for non-PD example/test material
When guessing key from first chord, use rel major if chord is minor.
placate hlint (redundant parens, mostly)
placate -Wall, largely

Just warns for missing top level sigs and
various "Defaulting the following constraint(s) to type `Integer'"
Tidy transposeChord: (fmap transpose possibleBassNote)
tidy transposeChord (no functional change)
flip upSemitones to make all of its current uses easier to read
support 6th interval, e.g. Am6.
Support 'sus' with no explicit interval.  E.g. Gsus9 (which is G9 sus4).

There's no need for us to capture this as anything other than text, for
now.
tidy and todo+
placate -Wall. minor.
tidy tests, and provide way to run the known-unsupported test cases