Turn on mic and set level on session startup
Turn on mic and set level on session startup

The microphone is turned off and set to a level of zero on startup.  A startup file was added to /etc/init to turn on and set the mic level when a session starts.

Change-Id: I5b350927d91b1d8168667beef33231cb61caac87

BUG=chromium-os:11689
TEST=manual, Ctrl+Alt+T and type 'amixer', verify 'Capture',0 enabled and set to ~80%

Review URL: http://codereview.chromium.org/6410072

joshfire/chromiumos-platform-init