Renaming fixture files in advance of supporting more than just PCM files
Generalizing exhaustive test support in advance of supporting more than PCM files
Generalizing constants ahead of supporting more than just PCM files
Adding ability for Writer to write sample data as 32 or 64-bit floating point data

I.e., Wave files with format code 3
Adding ability to read sample data from files with 32 and 64-bit floating point sample data

I.e., Wave files with format code 3
Removing no longer needed workaround
Updating test code to use the new preferred style for creating a Format instance
Fixing test to fully test what it claims to test
DRYing up duplicated test code
Changing Info.duration to return a Duration object, instead of a hash

Also removing Info tests that are duplicated in the tests for Duration in the process.
Updating README to include details about v0.5.0
Adding Reader.duration_read and Reader.duration_remaining
Minor README changes around v0.5.0 preview notes
Changing Reader and Writer attribute names from samples_<foo> to sample_frames_<foo>

This is a more accurate name for what these attributes return.
Renaming Info.sample_count to Info.sample_frame_count, which is more accurate
Renaming Duration.sample_count to sample_frame_count, which is more accurate
Expanding Duration tests to also test sample_frame_count and sample_rate attributes
Finish up append mode changes.
Merge https://github.com/jstrait/wavefile

Conflicts:
	lib/wavefile/writer.rb
	test/writer_test.rb