begin refactoring UserAdminPage to use ButtonPanel
make section choice "sticky" by saving it in the client-side session

Changed StatisticsPage and StudentProgressView to honor
the section choice in the client-side session.

This handles the case where the user chooses to see
statistics in a section for one problem and switches
to seeing statistics for another problem - they will probably
want to see statistics for the same section.
Merge branch 'master' of github.com:daveho/CloudCoder
changed UserAdminPage to use a ButtonPanel

This makes it consistent with ProblemAdminPage.
remove unused code
renamed StudentProgressView to ProblemProgressView

New name makes more sense because the view is used on
the page that shows statistics for a single problem.
started UserProgressPage: show progress of individual student in course
add a label with username/course at top of UserProgressPage
rename SelectedUser as UserSelection (consistency with CourseSelection)
implemented initial version of UserProgressView
hacking on code to get problems/subscription receipts for user

Trying to allow an instructor to retrieve all problems and
best subscription receipts for another user.

Doesn't quite work yet because the code assumes that the user
is requesting his/her OWN subscription receipts.  The database
query needs to be modified to allow the query if the requesting
user is an instructor, but otherwise allow the requesting
user to see problems that he/she would otherwise be
entitled to see.
allow instructor to get all of student's best submission receipts

Fixed getProblemAndSubscriptionReceiptsInCourse so that the
requesting user's id is used to check course registrations and
instructor status.
add combo box to UserAdminPage to allow section selection

Not actually implemented yet.
created SectionSelectionView, use it in StatisticsPage

This allows re-use in other pages where it would be useful to
allow section selection, such as UserAdminPage.
change UserAdminPage to use a SectionSelectionView
allow section selection in UserAdminPage
display UserAdminButtons and section selection on same row

This makes better use of space.  Also added a bit of vertical
separation between the buttons/section selector and the
user list view.
Merge pull request #39 from daveho/master

view user progress in course, improvements to UserAdminPage