refactor: fiduspad extends firepad and added fiduspad example

Attempt at extending firepad without changing it. Firepad code is kept
for now for reference.

Build script builds fiduspad.

Examples use built code and bower components. Examples include a page
with fiduspad. The editor can be accessed as `window.fp`.
feat(comment): Fiduspad emits event when comment is clicked.

Event is not yet tested.

Started on a CommentStore. Disabled PhantomJS, as it doesn't support
Function.prototype.bind.