After some discussion, we concluded that this code was unmaintained, not even used in
some places (display.cpp, units/frame.cpp), leaving the only area that really used it
at all the image surface cache. Considering there was never really a conclusive benchmark
of its benefits and because said surface cache will be used a lot less going forward,
we're just removing it and simplifying everything for everyone.
Closes#1260 since it's now irrelevant.
(cherry-picked from commit 3792612fb759942e6eb5de51364c2cca4ed16b40)
I also enabled /DEBUG:FASTLINK and /LTCG:incremental to speed up compile
times. VS2015 introduces support for both switches.
(cherry-picked from commit 3555b6278c2103391214e1da303d6c3e652387dc)
