Codechange: Replace custom mutex code with C++11 mutex'es.

A conforming compiler with a valid <mutex>-header is expected.
Most parts of the code assume that locking a mutex will never fail unexpectedly,
which is generally true on all common platforms that don't just pretend to
be C++11. The use of condition variables in driver code is checked.

Feature: Framerate display window (#6822)

Frame rate and various game loop/graphics timing measurements and graphs. Accessible via the Help menu, and can print some stats in the console via the fps command.

Fix: [Win32] Garbage in OS window title if branch name was too long.

This was caused by a missing \0-character on reaching the buffer limit.

(svn r26522) -Add: A config-file-only setting to disable usage of 8bpp video modes.
-Remove: [win32] fullscreen_bpp setting, which is replaced by above setting.
-Change: Disable usage of 8bpp blitters and video modes by default. Many modern OS and hardware cause issues with those.

(svn r26211) -Add: specialised non-animated SS2 blitter (MJP)
With 32bpp base set about 30% faster than 32bpp-optimized, or about 10% for 8bpp base sets in the Draw function. Respectively about 5 and 1% of total run time

(svn r16242) -Codechange: rework pausing
-Fix [FS#2864]: autopause and manual pausing conflict with eachother
-Fix: new game + pause on new game + autopause make the game not unpause on the first join

(svn r11734) -Change: Allow ToggleFullScreen to return the result of the operation' attempt. Previously, only visual clues were available.
-Fix[FS#1519]: When you can not use this resolution at full screen, now you'll know that it failed.
As for the reason it did not work, each computer/OS has its reason.

(svn r11480) -Codechange: Rename the function ALIGN fitting to the naming style
This fixes also FS#1450