is guaranteed to get a real contiguous array intead of a view.

2. Removed selectedOverlay command line argument.

3. Fixed x/y/zcentre arguments - they are now specified in terms of the
world coordinate system of the first overlay.

4. Fixed bug in fsleyes_parseargs._imageTrans - was not handling None

will change soon though.

it clears the pending flag for a GLOBject.

duplicate LBC/SC logic into a SC method.

so caller can tell whether shader state was actually
changed. GLVolume (for OpenGL 2.1) updated to use this feature.

schedule a 'create' function (to create a GLObject), as it was never
able to capture the GL context.

values (the master dctx inherits from the one remaining child).

texture changes).