adding codemirror for playground
#305: codemirror theme picker
copy pasta CodeMirror JS mode baseline 0.3.16 8214c1fa2c
adding license, source info, etc.
actually using new parser, etc.
fixing for loop
using semantic link and meta classes for highlighting
accepting relative links
adding basic autocomplete
removing @ autocomplete, leaving quotes alone
restoring @ autocomplete
doing token introspection to determine @ for autocomplete
fixing @ autocomplete swallowing cursor, selection keys
light styling of keywords in hint menu
removing errant, useless keyIdentifier reference to commercial at
removing regex-based IRI tokenizer

TODO: maybe revisit to figure out how to do this with the context?
cleaning up styles for initial load
cleaning up, removing jqyery-ui, using codemirror throughout
clean up, codemirror
removing no-longer-needed jquery ui assets