Merge branches 'master' and 'master' of https://github.com/learningequality/ka-lite into develop

Conflicts:
	README.md
ignore virtualenv generated directories
Merge remote-tracking branch 'upstream/develop' into develop
Merge remote-tracking branch 'upstream/develop' into develop
Merge remote-tracking branch 'refs/remotes/upstream/develop' into develop

Conflicts:
	.gitignore
	README.md
Adjust condition for return link.
Merge pull request #776 from wangguan59/back_page

Back link condition in exercise page
Enable zero-config with a specified admin and username.  Makes for full install on zero-config.
updates to undo unnecessary changes
Changing version for 0.10.2
Changing version for 0.10.2
Clear any existing user summary from DOM when rendering new graph.

Fix for #622
Fix for #464

When no users exist for Scatter and Timeline coach reports, show an error message instead of drawing an empty chart.
Update scatter and timeline no user error to use standard error communication.
Storing rarely modified properties in the user's session cache, to avoid unnecessary database queries. Remove double-call to main custom context processor, made Django toolbar REQUIRE CACHE_TIME=0
Moving code to appropriate middleware
Re-introduce fix that disappeared. Convert facilities in coachreports form data to ids.
implementing user sign-up restriction. extended config package such that multiple can be on, and added a config package for restricting users.
one more relevant spot
Added i18n documentation; updated the i18n management command to reflect some changes.