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.

Change: [Win32] Use Uniscribe instead of ICU for text caret handling.

This removes the need for the ICU lib on Windows.

Add: [Win32] Text layout using the native Windows Uniscribe library.

Uniscribe is sometimes producing different results compared to ICU, especially
when RTL and LTR content is mixed. Comparing the results to other programs
(like editors or web browsers) leads me to believe that the result are at least
not worse than ICU and possibly better.

Add: 32bpp SSE2 blitter palette animator (#6795)

Create a new blitter mode: 32bpp-sse2-anim, which is 32bpp-anim + this.
32bpp-sse2-anim is now used by default where 32bpp-anim would have been.
Also use this with the 32bpp-sse4-anim blitter.

See issue #6469.

Change #6685: Replace Win32 music driver with one not depending on MCI

MCI MIDI is poorly supported on newer versions of Windows and can cause large
delays at the beginning of tracks.

The new driver is based on a from-scratch reader for Standard MIDI Files. This
should be re-usable in other music drivers too, and can allow for finer control
of playback in general.

It also provides a better framework for reading MIDI data from other formats
than just SMF.

(svn r26214) -Add: specialised animated SSE4 blitter (MJP)
With 32bpp base set about 15-20% faster in the Draw function (slower with 8bpp base set). Overall, with 32bpp base set, about 5% faster.

(svn r26213) -Add: specialised non-animated SSE4 blitter (MJP)
With 32bpp base set about 40% faster than 32bpp-optimized, or about 10% for 8bpp base sets in the Draw function. Respectively about 8 and 1% of total run time

(svn r26212) -Add: specialised non-animated SSSE3 blitter (MJP)
With 32bpp base set about 35% faster than 32bpp-optimized, or about 10% for 8bpp base sets in the Draw function. Respectively about 6 and 1% of total run time

(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 r26205) -Feature: SSE 4.1 sprite sorter, improving the sorting performance significantly (MJP)
For example with GCC 4.8, x86_64 Linux, Intel i5-3337U this patch improves the performance of Pile, Treham and Hamac test save games by about 10% in over-all run time at fast forward at 1920x1080 when zoomed out and when trees are not disabled.