ui: split cusf_tawhiri_ui.js into separate files

Do nothing more than gather related items into separate source files as
per #82. Perform the minimal number of changes required to be
jshint-clean. These were fixing duplicate-var's, using line-breaks
likely to confuse the auto-insertion of semicolons and incorrectly using
{!=,==} with undefined.

No functional changes have been made with this commit.
ui: rename Prediction class -> PredictionCollection

As noted in #82, Prediction is better spelled PredictionCollection since
it more correctly reflects the actual nature of the beast.
ui: rename Path -> Prediction

As noted in #82, Path is more accurately spelled Prediction.
ui: refactor Request class into request_prediction function
Merge pull request #104 from rjw57/ui-refactor-issue-82

Split UI into separate files and refactor naming