Change pthread mutex's to be explicitly NORMAL instead of relying on the default...

Change pthread mutex's to be explicitly NORMAL instead of relying on the default on a per OS basis. Cygwin was using RECURSIVE as a default, which does not block the caller upon a second lock. This commit fixes decomb, and slow, and slower deinterlace on Windows.

git-svn-id: svn://localhost/HandBrake/trunk@1817 b64f7644-9d1e-0410-96f1-a4d463321fa5