Comment 50 for bug 722017

This patch should fix the OS X problems (#43, #44, #49).

Logic is now based on Marks suggestions in #45 :
* Changing the gradient name now changes the ID - there are no labels used.
* Gradient names are guaranteed to be unique and should be auto-renamed if the name is invalid, or clashing with an existing ID. The auto-rename logic is to append a random number to the end of an existing id - this logic has been in place (to ensure unique id's) for a long time and i dont know if we should mess with it.

@v1nce - even without the mesh button, 2 buttons for 2 different modes seems consistent with the other toolbars such as the Stars and Circles toolbars. Single toggle buttons seem to only be used for on/off types states.