Livelits

[gcrois]

This merge brings a implementation of Livelits, with some constant examples.

Examples:

1. Emotion (smile flashing bug?)
2. Timestamp (Can't keep up)
3. Slider
4. JS (Can't save result?)

Issues:

• Look up livelit in the context
• Show the livelits in scope in the context inspector
• Livelit names are showing errors
• When you press space after a livelit name, it should initialize the model argument and turn on the livelit projector immediately
• Only displaying correct view in smiley face projector every other update (may also affect other livelits?)
• ExplainThis sidebar should show information about livelit applications when relevant
• Create a documentation slide showing how livelits work
• Create browser tests and URL encoding PRs (currently they are already merged in here)

Limitations of projectors, to be fixed in separate PR:

• Livelit invocation must be directly surrounded by a parenthesis

Future PRs:

• User-defined livelits
• Splices
• Parameters
• Pattern livelits

2. Cannot define Livelits during runtime, Livelits don't have access to context -- this needs to be revealed to projectors
3. Cannot implement splices, similarly, requires context
4. Livelit invocation must be directly surrounded by a parenthesis in order to be grouped in InfoExp; example: (^emotion(100)) -- this is a limitation of projectors