Merge pull request #921 from FernetMenta/threads

Threads: add missing exception handlers.

I will be adding a PR to remove the circular dependency and provide a common, non-platform specific exception.

diff --cc xbmc/threads/Thread.h
Simple merge

diff --cc xbmc/threads/platform/pthreads/ThreadImpl.cpp
Simple merge

diff --cc xbmc/threads/platform/win/ThreadImpl.cpp
Simple merge