Export missing vgcontext*.h headers and remove libvgi.mmp due to collision with KhronosRI.
EXPORTS
_ZN16CWsBufferGraphic13HandleMessageERK6TDesC8 @ 1 NONAME
_ZN16CWsBufferGraphic13ShareGloballyEv @ 2 NONAME
_ZN16CWsBufferGraphic15UnShareGloballyEv @ 3 NONAME
_ZN16CWsBufferGraphic18UpdateWhiteLinePosEi @ 4 NONAME
_ZN16CWsBufferGraphic4NewLE4TUid @ 5 NONAME
_ZN16CWsBufferGraphic4NewLERK12TWsGraphicId @ 6 NONAME
_ZN16CWsBufferGraphic4NewLEv @ 7 NONAME
_ZN16CWsBufferGraphic5ShareE9TSecureId @ 8 NONAME
_ZN16CWsBufferGraphic7UnShareE9TSecureId @ 9 NONAME
_ZN16CWsBufferGraphic9OnReplaceEv @ 10 NONAME
_ZN16CWsBufferGraphicD0Ev @ 11 NONAME
_ZN16CWsBufferGraphicD1Ev @ 12 NONAME
_ZN16CWsBufferGraphicD2Ev @ 13 NONAME