Fix: popup menus were not freeing operators.
Made a new Popup menu call for this case:
uiPupmenuOperator(C, maxrow, op, propname, menustr);
It will set enum "propname" to the menu item and call operator,
register it optionally and free it. Use it in "invoke" calls.
Next: automatic menu generating for enum properties!
"operator.ED_VIEW3D_OT_viewhome(center=1)" calls the operator, converting keyword args to properties.
Need a way to run scripts in the UI for useful testing.
Still need to deal with operator exceptions and verifying args against operator options.
Added temporary WM_operatortype_first() to allow python to return a list if available operators, can replace this with something better later (operator iterator?)
