initial start at rewrite of fg_geometry functions, using glDrawArrays.

Tetrahedon done as example (seems to work well, but further comments
pending)
Done restructuring of the file as well

git-svn-id: svn+ssh://svn.code.sf.net/p/freeglut/code/trunk/freeglut/freeglut@1143 7f0cb862-5218-0410-a997-914c9d46530a