Added in code to assign timeslots upon confirmation

* Timeslot is assigned upon confirmation of the account through
  email.
* If the account is from any country besides China, a timeslot will
  be assigned based on a first come, first serve basis.
* Timeslot will be stored in the database using a millisecond format.
  Any part of the application that needs to display a nicely formatted
  time has to parse this millisecond format. This is made easy using
  the joda-time library.
Added a phone number watermarks on the registration pages.

* New WatermarkedTextBox widget that extends TextBox to support
  this function.
* Added in different watermarks for each individual country as per
  the phone number format for each country.
* NOTE: One must apply a cheap hack of calling .setText("") when
  changing the watermarks using event handlers due to some issues
  with the styling. An example of this can be found on RegisterScreen
  line 96.
Modified module path to reflect move to organization repo.
Merge pull request #2 from Ayrx/master

Timeslot // Watermarks // Changed Module Path