Improved UI for selecting class and format.

Improved the ui for selecting the class and format by making it simple.
before this we need to type the class and format in json string. added
new custom type selector control to make better.
Added Location HTML Control to add new event.

Added location html control to the add event. the control simpliifies
the input of location json during adding the event.
Adding location control to the edit evet modal.

Added the location control to edit modal view.
Merge pull request #37 from pryv/jaison

Improved UI for selecting class and format.