Extract function to toggle grid on/off
Extract functions to add colors and set the current color
Add key shortcut support for common actions

1-6: Select drawing tools (left to right)
g: Toggle grid
q: Zoom Out
w: Zoom In
Unify key-listening code for undo/redo and other shortcuts
Add key shortcut cheat-sheet to left panel
Capitalize 'Moved Pixels' for consistency
Bump version to 0.0.5
Merge branch 'AddKeyShortcuts'