Shaders : texture

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@30524 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#3899 better keyboard handling foe tfMax/tfMin

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@30525 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
allow Derivative[sin(t)] and Derivative[sin(t),2]

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@30526 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e