Buzz buzz!

Today's update adds a first pass on keyboard shortcuts for radial menus.

Eventually I'd like to use an underscore to indicate shortcut keys (like traditional mnemonic shortcut indicators), but I've been noticing some weirdness with underlines and custom fonts in Godot that I haven't found a solution for yet. I need to rework a bunch of how radial menus are constructed at some point in the future, so hopefully I'll be able to find some workarounds when I do that.

There's also a fix for the repeat shortcut allowing multicell upgrades to be built on single cells, destroying anything adjacent to them. Pretty sure that's a regression, but it was easier to just fix than track down.

Enjoy!

Full changelog:

• Added shortcuts for radial menu items
• Added settings option for showing radial menu shortcuts
• Updated right mouse click to select radial menu's back item if one exists
• Fixed inspect mode shortcut (Space) working when in a radial menu or a cell-specific screen
  Fixed scene input handler gobbling up radial menu right mouse clicks Fixed repeat upgrading not respecting multi cell requirements
• Fixed debug shortcuts working when in a radial menu or a cell-specific screen