Remove grep dependency, parse help string in python

[justinsalamon]

Calling grep breaks pysox (and subsequently) scaper on windows. This PR addresses this be removing the use of grep altogether and parsing the sox help string directly in python.

Addresses issue #66 in pysox, issue justinsalamon/scaper#25 in scaper

[coveralls]

Coverage increased (+0.002%) to 98.753% when pulling 3f71336 on justinsalamon:nogrep into 3ed47c9 on rabitt:master.

[coveralls]

Coverage increased (+0.002%) to 98.753% when pulling 6f92a54 on justinsalamon:nogrep into 3ed47c9 on rabitt:master.

[coveralls]

Coverage increased (+0.003%) to 98.754% when pulling 9d0e1de on justinsalamon:nogrep into 3ed47c9 on rabitt:master.

[justinsalamon]

@rabitt this is ready for CR and merge, just 6 lines.

[rabitt]

Looks good to me @justinsalamon , thanks for the PR.

@mthaak can you confirm that this works on windows?

[rabitt]

Also @justinsalamon can you squash the commits into one?

[justinsalamon]

@rabitt did that (squashing) work?

[rabitt]

@justinsalamon no I still see 5 commits in the PR.

Also waiting for @mthaak (or anyone with a windows machine) to confirm this PR fixes the problem on windows.

[justinsalamon]

@rabitt apparently you can setup the repo to have a "squash and merge" button instead of just a "merge" button - maybe the cleanest option (commits stay in branch, but squashed on master)?

https://blog.github.com/2016-04-01-squash-your-commits/

[rabitt]

Thanks for this @justinsalamon , and thanks for reporting @mthaak.