Several fixes for warnings.

  by Bernie Purcell <b dot purcell at adbglobal dot com> 

voutgl.m: support for VOUT_REDRAW_RECT in agl code, also added some smarts regarding handling null clip regions, which causes video flickers on Firefox/MacOSX when scrolling a page containing the mozilla plugin

- libvlc: new libvlc_video_redraw_rectangle() API, this allows caller to tell vout to redraw part of video, vout needs to implement VOUT_REDRAW_RECT message to support this

http Access: Make sure non-absolute relocation is handled properly in a https session (thanks courmish).

Mac OS X gui: checkForUpdate may not run on first thread. Hence alloc an autorelease pool in checkForUpdate.

	       * improve readability of macros	 

- getaddrinfo.c : cleanup replacement APIs for win32 and make sure the shim logic only searches for real APIs only once

- control/input.c: don't rely on exceptions to control the state of API internal logic as these are optional