Gtkvts testing suite

Gtkvts is a huge collection of tests for Gtk+ created by Sun and later forked by LSB. Fernando Herrera warned me about it some time ago when I was thinking about creating a test suite for Gtk+. Since then, I have spent some time reviewing it and it is really huge and complete, but has some things that I didn’t like too much: tests that are bad implemented or do not compile and the conversion tool they use to make the tests framework-independent among others. These issues drive me to think that developing tests from scratch could be a better approach this time. Anyway, we can still use gtkvts as a reference for lots of things, after all, there is a lot of work in it.