* glib/gtestframework.h: testing framework API as proposed on gtk-devel-list.
includes elaborate assertions, performance report functions, test traps,
test timer, test random numbers, teardoiwn garbage collection functions
and general test case / test suite management APIs.

* glib/gtestframework.c: first test framework implementation. already covers
some test suite management APIs and assertion message implementations.

* glib/tests/testing.c: test program for the testing framework.

* glib/tests/Makefile.am: complie testing.c as test. run all tests as part of
make test:.

svn path=/trunk/; revision=5877