E1791. Track the time that students look at the other submissions --> logging improvement (latest version)

[jerry-shijieli]

1. Transferred review submission link/file time logging code to the latest Expertiza repo;
2. Refactored 'respone_time' model to 'submission_viewing_event';
3. Set up 'submission_viewing_events' table to record starting and ending time of submission review;
4. Installed d3 library in bower for review time data visualization;
5. Changed Pie chart to Doughnut chart and added time distribution proportion on detailed submission review time visualization;
6. Add real-time saving of review submission viewing time;
7. Redesign popup detail page display content.

[coveralls]

Changes Unknown when pulling cebdfcd on WillSuen:master into ** on expertiza:master**.

[coveralls]

Coverage decreased (-0.05%) to 61.71% when pulling 1227346 on WillSuen:master into 3d78df6 on expertiza:master.

[coveralls]

Coverage decreased (-0.07%) to 61.69% when pulling 9afc724 on WillSuen:master into 3d78df6 on expertiza:master.

[coveralls]

Coverage decreased (-0.07%) to 61.69% when pulling d53c543 on WillSuen:master into 3d78df6 on expertiza:master.

[coveralls]

Coverage decreased (-0.07%) to 61.69% when pulling 7509a8a on WillSuen:master into 3d78df6 on expertiza:master.

[coveralls]

Coverage decreased (-0.07%) to 61.69% when pulling 2f61ebd on WillSuen:master into 3d78df6 on expertiza:master.

[coveralls]

Coverage decreased (-0.07%) to 61.69% when pulling 2f61ebd on WillSuen:master into 3d78df6 on expertiza:master.

[coveralls]

Coverage decreased (-0.05%) to 61.71% when pulling fd4ca20 on WillSuen:master into 3d78df6 on expertiza:master.

[coveralls]

Coverage decreased (-0.07%) to 61.69% when pulling 7aa1cc8 on WillSuen:master into 3d78df6 on expertiza:master.

[coveralls]

Coverage decreased (-0.05%) to 61.71% when pulling 7aa1cc8 on WillSuen:master into 3d78df6 on expertiza:master.