added dedicated method "resetWorld" to world
getting rid of the "x" close-icon. Not worth fixing as there are things I'm looking at now.
added mechanism to align the IDs of the morphs before/after complex morphs are created
adding a way for menus and the header of the inspector to show the MorphIDs but not the geometry details.
MenuMorph now actually opens within the world
big "updateRendering" refactoring. Main tests seem to be working but the current test suite is stale and doesn't pass yet.

…updateRendering was used rather loosely, and morphs were painting
themselves in their buffers too many times. This update clarifies what
this operation means and when it should be done.