Flip terrain heightmap and texture coords. Now the heightmap and texture are...

Flip terrain heightmap and texture coords. Now the heightmap and texture are used unaltered - the terrain looks like the texture/heightmap when looked from high above.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@1812 dfc29bdd-3216-0410-991c-e03cc46cb475