Added build script allowing use of different toolchains
holdingarea/build.bat provides command-line switches allowing:
* Selection between Visual Studio versions (2005 / 2008)
* Selection of debug / release builds
* Selection of CMake generator (Visual Studio solution / NMake makefiles)
* Enabling of miniEGL in the build
* Enabling of PlatSim extensions in the build
Calling the script with no parameters will start a build using
Visual Studio 2005 and nmake.