User experience updates

Hello all. After receiving some feedback on the user experience, namely that it was confusing and difficult to use on larger screens, I've set about updating it to be more user friendly.

• The top and bottom toolbars have been re-designed to work better on any size of screen. The contents are now condensed and centered on the screen.
• Actions and attributes are now always visible. Previously you had to tap on a tile in order to see what actions and attributes it had. Now actions and attributes which belong to a tile are displayed on the tile.
• The selection and moving of an action from one tile to another has been replaced by the concept of "global" actions. Previously, actions always belonged to tiles and if the tile did not contain a lock attribute, you could select it from one tile and move it to another. Instead, unlocked tiles are now available in the toolbar to use at any time, unless they become locked to a tile.

That's encompasses most of the visual stuff. There was a significant amount of refactoring behind the scenes to get it all working, but hopefully it provides a simpler and more intuitive user experience.