Cross-platform compatability

I have neatened up the modifications for cross-platform compatibility. The unit tests will still not compile in MSVC due to some strange library linking error. If you check out th latest version of the software for use in an MSVC environment, it is neccessary to edit the following files as follows:
1) modules/modules.pro - remove "skethcer" from the subdirs variable because the sketcher module is not yet part of the code.
2) trantoo.pro- remove "tests" from the subdirs variable because they don't work in windows.