Add module display name to module related server events

This information will likely be used frequently for analytics purposes, so we would like to denormalize here to avoid having to join with the modulestore later.

Fixes: AN-594
Merge pull request #2696 from mulby/gabe/add-problem-name-to-events

Add module display name to module related server events
Variable-ize "Certificate of Achievement" text
Merge pull request #2551 from edx/giulio/custom_cert_names

Variable-ize "Certificate of Achievement" text
Also clean up the 3rd-party po files.
Generate now removes format flags.
Updated po/mo files without format flags.
Merge pull request #2707 from edx/ned/clean-up-i18n-tools

Ned/clean up i18n tools
Add map to problem_check event with descriptions of student answers

The map contains a human readable description of the answer if
necessary. It is useful for problem like multiple choice, when the
response of the student is replaced by a moniker. For example "choice_0"
instead of the full text.
checkpoint