Add basic tooltip functionality and implement object_info_request and object_info_reply messages.

IPython has a tooltip feature which shows an info box under the cursor containing info about the current object. I have ported this to IHaskell. Basically, tooltip.js sends an object_info_request message to the kernel and the kernel responds with type information about the closest object.
Merge branch 'directives' of github.com:edechter/IHaskell into directives

Conflicts:
	deps/tooltip.js