* Update design with materialize and new form builder

* Update to new datetime picker

* fix styling issue with user search box

* Minor fix to delete option

Used flatpickr lightweight datetimepicker for DateTime input. Works with Datetime or just Date. Uses same ruby form templates

with master

* Start adding materialize components to FormBuilder

* Finalize input styles

* Add table for assessment problems

* Minor dropdown changes

* change datepicker class

DATETIMEPICKER NOT FINISHED

* Convert assessment page cols from bootstrap to materialize

* Convert initial collections and cards

* Add styles and html for Danger Zone

* Add Danger Zone to CA options and Admin options

* Make handouts and table materialize format

* Use browser default confirm dialogs

* Remove deprecated leanModal

* Remove bootstrap tooltip

* Fix tooltip message on submissions

* Update courses index page

* Update Assessments index page

* update course list display logic

* Add materialize style to course and assessment card pages

* navbar_icons

* button fixes

* Change lab template image to autograding_image for use with Tango Docker

* Bump ruby version for rspec testing framework

* Add mysql gem to Autolab2.0

* navbar_icons

* button fixes

* Start adding materialize components to FormBuilder

* Finalize input styles

* Add table for assessment problems

* Minor dropdown changes

* change datepicker class

DATETIMEPICKER NOT FINISHED

* Convert assessment page cols from bootstrap to materialize

* Convert initial collections and cards

* Add styles and html for Danger Zone

* Add Danger Zone to CA options and Admin options

* Make handouts and table materialize format

* Use browser default confirm dialogs

* Remove deprecated leanModal

* Remove bootstrap tooltip

* Fix tooltip message on submissions

* Update courses index page

* Update Assessments index page

* update course list display logic

* Add materialize style to course and assessment card pages

* navbar_icons

* button fixes

* Change lab template image to autograding_image for use with Tango Docker

* Bump ruby version for rspec testing framework

* Add mysql gem to Autolab2.0

* navbar_icons

* button fixes

API requests (e.g. annotations) should not try to display
donkey kong when they fail, since that just triggers another
error

fork with a block does not seem to propagate exceptions in the subprocess
to rescue blocks outside the fork block, so exceptions inside scheduler
modules were not being logged. Trap them inside the fork block, also trap
ScriptError exceptions, and send the subprocess exceptions to
ExceptionNotifier.

Since moss can run for an extended period of time, it is possible
for database connections to time out while it is running. ActiveRecord
does not check database connections for liveness whenever they are used,
only when they are checked out or back in to the connection pool.

Make activerecord return all active connections to the pool before running
moss, so any post-moss database access will use hopefully-live connections.

implement cache on gradesheet page to save on change only

Faster Gradesheet (on-demand feedback and deferred rendering)

add searchable dropdown to create submission page

Add searchable dropdown and datepicker to extensions page

The file opened during local_submit is controlled by the student. Make
sure it's not a symlink. Uses O_NOFOLLOW, so no part of the path may be
a symlink

if the request came in over http (e.g. local_submit), then
the generated autograde_done url will be http, and will be rejected
when tango uses it