* standardise program/sox.py formatting, add test case
* add program/sox.peak_level() docstring
* update .travis.yml to include sox as a test dependency
* move sox from test dependency to normal dependency
* update README to mention sox, remove small autoconf mention
* use .splitlines() instead of .split('n')
* update README to force python2
* add support for PRE_EMPHASIS detection; mark pre-emphasis as FLAGS PRE in .cue
* correct typo, s/ivar/type/ for pre_emphasis element in track table
* add SoxPeakTask, program/sox module, sox.peak_level()
* use sox peak detection in lieu of gstreamer
