Scroll blockly

@kadst43 Allows scrolling vertically in the blockly interface, and for screens shorter than the default blockly height, makes the interface the same height as the window.

EDIT: Trouble with the height changing is that, if a user opens the app in a smaller screen, then resizes to a larger screen, the interface will stay the same shorter height. 
Unfortunately, we cannot do this. Dragging a blockly block from the pallet fires a window resize and centers the window. I did this before and had to remove it.