Add info about Mandarin Chinese option to LMS
Merge pull request #4149 from edx/sylvia/docs/release_notes_6_16

Add info about Mandarin Chinese option to LMS
Tracks last edited date and user, and adds has_changes for blocks.
link to code ownership page from CONTRIBUTING.rst file
Merge pull request #4152 from edx/db/code-ownership

link to code ownership page from CONTRIBUTING.rst file
Wait for scripts defined in common xmodule code to execute.

STUD-1792
Merge pull request #4060 from edx/benmcmorran/edit-tracking

Tracks last edited date and user, and adds has_changes for blocks
Remove locator.py (now sourced from the external opaque_keys library)

[LMS-2757]
Merge pull request #4113 from cpennington/remove-locator

Remove locator.py (now sourced from the external opaque_keys library)
Removes DateTuple field type
Merge pull request #4119 from edx/christina/requirejs-promise

Wait for scripts defined in common xmodule code to execute.
Merge pull request #4154 from edx/benmcmorran/remove-datetuple

Removes DateTuple field type
stop update_assets commands from being called extra times