Initial work on note searching functions.

Still very fragile. In particular:
- If no notes are downloaded before the search is used,
  no notes layer exists and bad things happen
- No URL escaping on the search term
- No icon
- Not sure how this will interact with the action queue
  in offline mode
Search action class

Forgot to commit this the other night
Improving search functionality.

General improvements. Mostly adding an icon and handling offline mode.
URL encoding search term
Adding support for additional search parameters

Now supports specifing values for the "closed" and "limit" API options.
The plugin defaults to 1000 notes and only open ones.
Formatting whitespace
Initialize notes layer if needed on search
Adding config keys for note search options
Turning the API download limit into a variable
Adding configurability to the search feature
Fixing whitespace. Eclipse is silly sometimes
Merge pull request #15 from iandees/search

New Feature: Search