Removed some commented lines
Relaxing validation checks for objects created before 2013

But have to make sure that worksheets continue getting created. They
had stopped being because of validates_associated clause in student and
teacher models
Registration forms in modals - not dropdown menus
Validate sektion code during student registration
[vertical/topics]: Ensure that only topics that have some questions are enabled when building a quiz
Merge remote-tracking branch 'heroku/master'
- cleaned up reference
[Bug]: Do NOT override methods added by associations ...

Problems adding a new sektion for a teacher w/ no prior sektions
Merge branch 'master' of heroku.com:drona
Clear form on successful submission
Merge branch 'dev'
Two new query methods to find empty/non-empty sektions
Added method to render .single-lines within columns

The number of columns in inferred from the # of div.column within
 the specified target
Defined behaviour of clicks on .single-lines that are within columns

For now, its the same as click on any other single line anywhere else
Sharpened logic for replacing any :prev or :id within data-action
[sektions]: Update action sends back its own JSON

JSON has info on which students were removed from a sektion and therefore
which names should now be hidden
[teacher]: Modified interface for editing a sektion
Merge branch 'dev'
Added methods to encrypt / decrypt database IDs

Testpaper and student IDs will be encrypted to form the QR code

They will be decrypted during receive_scans and unresolved resolution
Split methods siblings? into 3 more precise queries

siblings_same_worksheet => same student, same worksheet
siblings_same_page => same_student, same worksheet, same page
siblings_same_page => same_student, same worksheet, same question
   (necessarily returns [] for standalone questions)