Replace <textarea /> with ACE editor and use FBP syntax highlighting

[johnrees]

A less cluttered commit (without bower_components included), on another branch https://github.com/johnrees/visualize/tree/ace-editor can be seen here: https://github.com/johnrees/visualize/commit/37692009de167ca2b9864ca39d3d0a9ee12da6e5

Demo running here https://johnrees.github.io/visualize