Unit tests framework integration

Currently unit testing has been implemented for libchcore and it's being handled by a separate project with tests.
There are issues with this design, as we're not able to test some internal library code.
Also there are other projects where the unit testing framework is not implemented at all preventing tests from being written at all.

What we want to do:
1. Include tests for libchcore within the library itself (only when compiling in a special configuration)
2. Include the unit testing framework in all other projects (dll and exe).
3. Make those tests run as a part of the build (also, only in some special configuration).