Get Code Templates to start working

Fixes #264.
Code templates are listed in completions. Parameters for templates seem to work ok. 
I don't know the intricacies of code templates, so there may be more work to do.

Work for some other day:

* As it is now, templates are always listed in completions. This clearly needs to be refined. If you dot into an object, you should not see code templates. 
* No code templates ship with MD for F#. Not even a template group, so user needs to manually create a group and set its correct mime type (`text/x-fsharp`). I'm hoping @7sharp9 may have already done some work here for vnext? We can not add pre-installed templates from the binding, those go in MonoDevelop itself.