orignal seperate headers and source into include/osg/UnitTestFrameWork
and src/osg/UnitTestFramework.cpp respectively. I have done this to
keep the include and source directories focused on the scene graph rather
than the test framework.
Have added a very simple unit test to Vec3.cpp, which are optionally
compiled in with the OSG_COMPILE_UNIT_TESTS define, which is only
currently defined in debug builds under unix. It should be fine to
add it in under Windows project files as well.
Finally, a new demo app osgunittests runs the tests and reports success
or failure of the tests.
