Windows WML tests: Add WindowsTimeout project

As the --timeout option for Wesnoth can stall the process, we replace it
by an encapsulation comparable to the Unix timeout function.

WindowsTimeout isn't limited to Wesnoth, it can in fact set a timeout for
any executable called through it.

An example on the use of these WinAPI functions can be found on
http://msdn.microsoft.com/en-us/library/windows/desktop/ms682512.aspx
Windows WML tests: Port .sh test script to .cmd

WML tests are read from wml_test_schedule, executed and their error code
is compared to the expected result.
Windows WML tests: Improve stdout output

Differentiate between timeouts and real errors: In case of a timeout, only
throw a warning instead of an error.

Also implement a basic progress bar.
Windows WML tests: Add optional argument for executable path
Windows WML tests: Enable automatic tests in VC
Merge pull request #173 from aquileia/WML_test

Add support for WML unit tests to the VC compiler, and also a nice windows cmd script, porting the bash script which we have, and which uses a timeout program which Aquileia wrote for us and added to the VC project files.