skins2 manages a cache for building layouts. Yet, on each redraw/expose,
it rebuilds the whole layout. This patch avoids these unnecessary rebuilds.
It results in dramatic improvement, especially on Linux, where refresh was a real issue.

On X11, windows are created with a 1x1 size and updated later on.
In some context, vout_display can catch this 1x1 size before the size is updated.
This results in a crash in swcaler.c which gets a 1x0 size (division by zero)
Changing default to 10x10 solves the problem.

Revert "Win32: fix #2592 (stdin file input). It may impact other platforms, so please test, and fix/revert if you see a bug."

This reverts commit e33a82db.
This broke opening any file starting with a dash.

This enables passing a below state in addition to currently supported
always-on-top (above) and normal. (However, none of the window provider
support it just yet).

Should fix aspect-ratio issues and fixes #2793

Win32: fix #2592 (stdin file input). It may impact other platforms, so please test, and fix/revert if you see a bug.

configure: Make sure independant Mac OS X-related modules can be activated/deactivated individually.

Else, this results in triggering the timeshift module.

Modified the main OS X interface module to remove the use of setjmp() and longjmp(). The MainMenu.nib file was modified to invoke the stop selector instead of the terminate selector on the NSApp object. This allows the OS X framework to return from the call [NSApp run] instead of using setjmp()/longjmp() in a managed framework.
Signed-off-by: Pierre d'Herbemont <pdherbemont@free.fr>