Howdy! I've just pushed version 3.3.9, which improves casting controls and allows you to control more things with the mouse; here's an excerpt from changelog.mk:

• Added the 'hotbar' for spells/ranged/abilities
• Added click to move, right click to attack (uses 'A' in hotbar)
• Added autopickup of stackable stuff you already have in your inventory
• Added mouse zoom (+/- on numpad for keyboard shortcut)
• Removed item stack 'halving' and replaced it with 'right click to use'