Antimony 0.9.3

Features

• Use alt modifier to drag values faster
• Add 'Show math string' node
• Pre-emptively clip rendering to screen size (which should make rendering faster when zoomed in)
• Easier packaging for Debian (thanks @pfelecan)
• Flatter icon (thanks, @ApostolosB)

Bugfixes:

• Tab and shift-tab now switch between datums like they used to (before 0.9.1)
• HSB color node is no longer black by default
• Fix extra images being drawn on load
• 'Hide UI' menu item actually does what it says