Release 0.4.4

• API change: Added backend to InlineGUI constructor.
• Improvement (Experimental): Added simulator hooks
• Improvement: Added audible spike sounds
• Improvement (Experimental): Nodes have access to the GUI keyboard state
• Improvement: support for nengo-bio Connections
• Improvement: show multiple connections between objects
• Bugfix: handle new Connection transform in Nengo 3.0.0
• Bugfix: escape labels so they aren't treated as HTML
• Improvement: reworked networking to allow clean integration with Jupyter