xBRZ trial commit

(See screenshots here: http://imgur.com/a/zeou4#0)
(Description of xBRZ here: http://en.wikipedia.org/wiki/Image_scaling#xbr_family)

This commit adds the xBRZ algorithm to the codebase, and hacks in
an imagepath modification to use it, and adds a bunch of extra
images showcasing it to the unit help pages.

xBRZ was obtained from sourceforge (xBRZ.zip):
http://sourceforge.net/projects/hqmame/files/

It is modified, the original program wants to be compiled as
C++11, so I had to make minor changes so that it can compile as
C++98 w/ boost.

Main changes: get boost/cstdint and typedef uint32_t from there,
comment out all static asserts
change all cases of lambda functions to boost bind instances or
otherwise.