Every menu item is a control in __UI_Controls. Needs visual polishing. Functionality is implemented (except keyboard). Also:
- New TIMER approach for DoEvents.
- Menus are now accessible using Alt.
- More default settings are automatically defined upon control creation.
- Dropdown now lists have hover to select behavior.
- Alt+ASCII CODE inserts extended characters.
- Font set for the main form is inherited by new controls.
- All control images are now converted to hardware images.
- Replaced "Enabled" with "Disabled" for control properties (new control properties always default to __UI_False)
- Removed calls to _MOUSESHOW in Linux, for increased stability.
- Exposes MessageBox from libqb.cpp (QB64's internal declaration/implementation; uses Windows API or an emulated alternative under Linux/macOS)
- Scrollbar accepts clicks on the "track".
- Adds a __UI_DoEvents routine that is triggered in the main loop and can also be added to user loops, in order to allow events to keep being triggered.
- Visuall indicates that something is hogging the input routine (when programmer has a DO: LOOP and forgets the add __UI_DoEvents)
- ListBoxes can be searched by typing item names.
