Code review comment for lp://staging/~elementary-apps/maya/maya-saucy

Okay, a lot of changes now:

* Implemented the deletion according to the HIG conventions (providing an Undo button)
* Implemented the modification of calendars
* Removed the radio button (for the default calendar when creating an event) the user has to check the box when editing the calendar to make it default.
* Changed the color to Blue by default
* Added placeholder texts in every entry to show you example (you can enter your google user name if you have an @gmail.com or type the full address, it's detected afterward)
* Check for the calendar directly after the creation (and thus ask for a password if needed)
* Some ports to the new libecalendar and added required functions to the .vapi