Fix uninitialized value
Merge pull request #83 from ywwg/keylock-fixes

Fix uninitialized value
Fix string comparison for architecture detection in mixxx.py. Fixes Bug #1235711.
Use hostapi enum instead of string to test for JACK.
Only use 2-channel input processing optimization if there is one AudioInput and it is a stereo input.
When using ALSA, open devices configured for mono-only in stereo to workaround Bug #900364. Tested on Linux and by forcing the workaround on OS X.
Add dedicated path for processing the single configured input case for a 1-channel device (a tiny speedup for microphone processing).
Don't use currentDateTimeUtc() as it was introduced in Qt 4.7.
Allow mutation of userLocale in loadTranslations (fixes build for Qt < 4.8.0).