New: Add "coverage" and "python-coveralls" to requirements.txt

I'm working on automated automated-test coverage reports with coveralls.io.
New: Coveralls.io Support in .travis.yml

Let's hope it works... !
Fixed: Update README.txt (also add coveralls.io to Same)
Fixed: Fix Travis's "script" Command
Fixed: Consistent Citation Year in README
New: Add .coveragerc File

Should have been in here a few commits ago. Oops!
Merge branch 'master' into devel_2
Fix: Revise run_tests.py to Return non-0 Status on Test Failure

Previously, the script would return 0 unless there was an error with the file
itself. This was fine for humans reading test results, but it doesn't work with
Travis-CI, which needs a non-zero status to signify failure, so failing builds
where showing up as "passing" on Travis.

This also means the script stops on the first failure.
Merge branch 'master' into devel_2

Conflicts:
	run_tests.py
New: Add Short Palestrina Test Piece

It's the first Agnus Dei from dude's Missa L'homme armé (1582).
Fixed: IndexedPiece.get_data() Handles music21.stream.Stream Objects Correctly

We didn't properly re-import the piece for analyzers requiring Part or Score
objects. Now we do.

Closes #289
Merge branch 'devel_2' into diss_sigs

Conflicts:
	run_tests.py
WIP: Some Changes for Dissonance Signatures

This isn't very clean work at all.
Some corrections to the SuspensionIndexer
New: Provisional NeighbourNoteIndexer

It doesn't check metric limitations yet. It's also completely untested.
New: setting for FilterByOffsetIndexer

Now the 'method' argument can be changed. It's default is still 'ffill'.

Related to github issue #305
New: optional parameter in WorkflowManager._run_off_rep()

Added optional parameter called is_horizontal which changes the 'method'
setting in FilterByOffsetIndexer. If is_horizontal is set to True, method
will change to None. The default for is_horizontal is False.

Related to github issue #305.
Did some stuff
Did some stuff
Docs: in an example in offset.py

The example in offset.py lines 128-146 needed a minor edit to
incorporate a dissonance where the text description called
for one.

Closes #308 on github.