fixes GLES2Renderer->ofProgrammableGLRenderer

* we'll need to check this with all examples, eventually.

Signed-off-by: tgfrerer <tim@poniesandlight.co.uk>
fixes a nasty bug

* resolves an issue where 'leftover' vertex buffer attributes would fall GL_DRAW_ARRAYS to fail since the buffer would still be marked as ENABLED in the VAO. Releasing the vertices of a mesh upon unbinding resolves this.

* adds some safety checks, disabling color, normal, texCoord and index data upon mesh assignment if not present in the data that is to be set onto the mesh

Signed-off-by: tgfrerer <tim@poniesandlight.co.uk>
typo

Signed-off-by: tgfrerer <tim@poniesandlight.co.uk>
simplifies built-in shaders, resoves a couple of drawing issues

* simplifies built-in shaders to have just the bare minimum code needed. no bugfix hacks anymore =)

* resolves an issue where usecolor and useTexcoords would not be pushed to the built-in shader correctly

Signed-off-by: tgfrerer <tim@poniesandlight.co.uk>