Added a new, dedicated worksheets controller
Added a detach() method to overlay
Reworked the student console ...

There are now only 3 main links - assignments, lessons and enroll
Merge branch 'master' of https://github.com/abhinavc/web-application
 minor bug fix
Welcome mail sent twice .. Leave it to after_create callback in Account
Minor edit to view-feedback panel ...

Last tab given an icon instead of text
Initial commit of new feature to show item-count within a horizontal tab

Depending on the context, we can now a show a number that lets
the user know how many of the relevant items there are.

The context could be
   1. how many quizzes are there in a student's inbox / outbox
   2. how many exams a grader still needs to grade etc. etc.

** Periodic updates ** has not been implemented. It can be, but:
  1. it will be a bit complicated - requiring regular pings to the server
  2. possibly unnecessary given that few item counts will change dramatically
     over a typical session. Our system is not like Gmail where many post
     to one account. Most of our data is slow changing
Minor corrections
[examiners]: Show only exams pending for a max. of 15 days ...

There is too much noise in the system otherwise and new work
gets lost amongst that which we do not plan to do
Return marks out of how many for mobile display