Initial commit of Class Flags models.
Adds ClassFlag and ClassFlagType admins.
Adds flag_types to program creation form.
Adds flag query builder interface.

Right now there is nothing to accept the submission, but the flag query
builder interface is basically done.
Adds flag query results page.

Also some small changes to the models, adding seq, color, and some
uniqueness constraints, and some small changes to the flag query builder
page.
Adds flag editing interface on manageclass and on flag query results.

Coming soon to editclass.
Adds class flags interface to editclass

Only adds it to the manage version, although updates the checking for
that to always include /manage///editclass/#### rather than requiring a
GET or POST as the dashboard buttons produce.  (This is basically for
convenience for those of us who type the URL manually.)  Also some minor
fixes to other parts of flags.
Adds more class info to flag query results.

This involves factoring a chunk of the manageclass template out into a
different file to avoid duplicating a lot of code.
Adds class flags to classes and teachers in dashboard

Actually, the teachers list was already there, but now it actually
works.
Fixes to class flags.

Changes flag_types() to ClassFlagTypes.get_flag_types(), adds list of
flags to the dashboard status pop-up, removes unique_together on flags,
and some other minor fixes.
Really fixes to class flags now.
Merge pull request #901 from learning-unlimited/class-flags

Class flags