Fix saving error of video editor in non-english translation

Currently the code in ```tabs-aggregator.coffee``` uses the display name of a tab as the key to index the current tab. When a non-english translation is applied, the javascript code will get localized names instead of the original english names, which causes the following ```getValue``` function fails as it cannot reference the correct tab.
Use the 'data' attribute to store the original tab name.
Do not look for country if no new ip.
Fix modulestore merge conflict with heartbeat.
Corrected event name in description
Merge pull request #4235 from edx/ahodges/documentation/DOC639

Corrected event name in description
Merge pull request #4233 from edx/alex/geoip-none-ip-fix

Do not look for country if no new ip.
PR 2571, log stop_video event
Merge pull request #4242 from edx/ahodges/documentation/DOC367

PR 2571, log stop_video event
Updated for PR 4106, BLD-1134
Merge pull request #4243 from edx/ahodges/documentation/DOC657

Updated for PR 4106, BLD-1134
Merge pull request #4239 from edx/release

Release
Merge pull request #4236 from edx/nimisha/fix_ms_merge_conflict_heartbeat

Fix modulestore merge conflict with heartbeat.
Merge pull request #4217 from louyihua/master

Fix saving error of video editor with non-english translations
Fixed IE security warning on course page.
LMS-2892