Integrate libRocket tests into VisualUnitTest framework

* Introduce ::set_init_rendering_callback getter & setter methods
for VisualUnitTest; this is necessary for the bit of custom init
still required by libRocket at this point.
Introduce option to disable color logging

This feature is for clean logging output when the output console
does not support color (i.e.: Sublime Text Editor view). It currently
depends on the environment's shell variable NOM_COLOR.

* Implement UnixFile::env
Fix usage of multiple event listeners per element

* Events are now held in a std::map and iterated through in
::ProcessEvent.

* Re-enable keydown and mouseup event listeners in EventListenerTest.
* Rename internal variables of UIEventListener.
Add an element ID name to the question message
Disable XML build unit
Fix MSVCPP compiling errors on WindowsOS

* StateMachine: MSVCPP didn't seem to like the double std::move
action going on in ::set_deferred state -- and I can't say I
can blame it after looking at the mess of the logic!

* sdl_helpers.hpp: Fix macro collision with RGB function that can
happen depending on inclusion path with wingdi.h -- commonly from
including windows.h.

* Size2.hpp, Color4.hpp: Fix another macro collision with std::min
and std::max that can happen depending on inclusion path with
windef.h / windows.h. This one is just flat out dumb!
Implement WinFile::env && introduce additional NOM_COLOR options

* Introduce WinFile::env so that WindowsOS can make use of the
NOM_COLOR environment variable the same as Unix platforms.

* Introduce boolean TRUE values: '1', 'true',  'always', 'yes' and
remove check for 'TRUE". The case-sensitive value has been noted.
WindowsOS build for libRocket

This introduces new dependencies under Windows; GLEW, libRocket and
FreeType2. The published binary dependencies can be found at
https://sourceforge.net/projects/nomlib/files/

* Add 'OpenSans' && 'OpenSans-Bold' to nomlib's Resources/fonts
directory for both OSX & Windows to access.

* Add LICENSE file for libRocket.