Fix/Workaround bug #591
Fix/Workaround bug #591

We could check for the extensions but these OpenGL options are never used,
so no need to disable them.

janisozaur/opentoonz,m-grimaud/opentoonz,janisozaur/opentoonz,janisozaur/opentoonz,m-grimaud/opentoonz,damies13/opentoonz,m-grimaud/opentoonz,janisozaur/opentoonz,lordadamson/opentoonz,lordadamson/opentoonz,lordadamson/opentoonz,lordadamson/opentoonz,damies13/opentoonz,damies13/opentoonz,janisozaur/opentoonz,lordadamson/opentoonz,damies13/opentoonz,m-grimaud/opentoonz,damies13/opentoonz,m-grimaud/opentoonz