[~] Linke OSX build against GLFW
[~] CGraphicsPluginPsp doesn't need to be visible outside the .cpp file. Also tidy things up a bit.
[~] Define a virtual dtor to keep the compiler happy (actually seems ok for PSP compiler, but clang was complaining for OSX so keep them consistent)
[+] Add a simple GraphicsPlugin implementation for OSX. Just draws a triangle on each call to UpdateScreen right now.
[~] Remove NativeTexture fields that are only used by the PSP build.
[~] Silence a warning about an unused variable
[~] filepath can never be null here \!
[~] malloc.h doesn't need to be included (not present on OSX)
[~] Group some common headers in GraphicsPluginPSP.cpp
[~] Fix indentation
[~] Make some const casting clearer
[~] Avoid casting away constness
[~] Move gFrameskipActive to DLParser.cpp
[~] Add a GraphicsContext.cpp for OSX
[~] Tidy CGraphicsContext::Create for PSP
[~] Tidy CGraphicsContext::Create for PSP - impl is in .cpp file so don't bother with protected members and friends
[~] GraphicsContext UpdateFrame return was unused. Rename GetBufferSize to GetScreenSize, and use to avoid exposing SCR_WIDTH/SCR_HEIGHT
[~] Add a Round function to Math.h, to provide some platform independence for pspFpuRound
[~] ifdef out some PSPRenderer code so it compiles on OSX
[~] Get lots more graphics code compiling and linking for OSX. Get runtime asserts when unimplemented dummy sceGu functions are called.