[MAT-468] attempted fix of int/uint comparison issue

Signed/unsigned int comparison is picked up better by gcc 4.9+.
This fixes up the locations it identifies.
[MAT-468] patch to turn off int/uint comparison check

gtest 1.6 (and 1.7) refuse to build with -Wall due to signed int
to unsigned int comparision. This patch overrides the flag.
[MAT-468] Bump locations of system libs.

This updates the default location of the system libraries as
found on our build farm.
[MAT-468] unify platform target names.

This goes some way to making sure all platforms are called by
unified code names [lnx,osx,w32,w64].
[MAT-468] Fixing up native loader.

This patches the native loader code with respect to the new
unified platform naming scheme.
[MAT-468] Patch up combine.py.

This patches up the combiner code with regards to the new unified
platform naming scheme.
Merge pull request #129 from OpenGamma/MAT-468

Mat 468: patch up sources following build system upgrade