[Catty] features and fixes IDE (#79 #117 #127)

- edit menu for bricks and scripts
- delete a single brick with edit menu "Delete" item
- delete a single script with edit menu "Delete" item 
- edit mode for scripts with "Edit" button in navigation bar
- focus tapped brick changes
- adding new bricks in last visible section (script) on screen (not final solution)
- refactoring and fixes