Added Neil Salter's osgUtx library into the distribution, have put all the

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.

Make/debugtests.bat

@@ -2,6 +2,10 @@ echo osgversion
 osgversion
 more memleaks.log
 
+echo osgunittests
+osgunittests
+more memleaks.log
+
 echo sgv osgcool.osg
 sgv osgcool.osg
 more memleaks.log