[freetype][PPC64LE][PATCH] Update freetype to 2.6

Updates builtin_freetype to 2.6 (current upstream version), which can
detect PPC64LE machine.

This was compile tested on SLC6 + ICC + x86_64 and F21 + GCC + ppc64le.

README was removed, because no issues were noticed with ICC compiled and
-Wall -pedantic -ansi flags.

Additionally --with-png=no --with-bzip2=no flags are passed to freetype
configuration script. Default values for these options are auto.
freetype find libpng and libbzip2 on the system and builds extra
modules. Then attempting to link to freetype you would need to link
-lpng -lbzip2 exlicity, otherwise linking will result in undefined
references.

Otherwise we would need to check for libpng and libbzip2 on the system
and adjust FREETYPE_LIBRARIES to include -lpng and -lbzip2.

The current solution goes for the minimal configuration.