registration using mobile
Merge remote-tracking branch 'upstream/master'
Merge pull request #197 from adamarla/master

Changes to accomodate registration via mobile app
Temp commit - need to fix a bug in master

Do *not* revert to this commit !
There is ** no need ** to separately compile take home/abridged worksheets ...

We show the versioned jpeg for the questions in the worksheet. That is
enough.
mode = 'worksheet' when compiling worksheets
Corrected run-time error due to differing struct sizes
Merge branch 'master' into puzzle
Not going to bother with tweaking rubrics
Reverting to old rubric/criterion behaviour ...

will create a new quick grade infrastructure for stabs.
No method shortcut? in Criterion
Slight cleanup before grading panel for stabs implemented
Added a non-string uid for stabs that can be used for quick lookup ...

The uid is basically the integer representation of the date on which
scan for a stab is received.

Unlike 'scan', it is just the date and does not have sha1sum.
More than one stab can have the same uid. But as uid is indexed,
lookup can be quick.
Group stabs by the date they were received on using the integral UID
 removed redundant code
Rationalized models for stabs. Prepped now to grade them