updated pdf viewer
Add some optional policies around password resets, such as password reuse, forced password resets, allowed frequency of password resets
password history: just limit the result set range to simplify iteration logic
Fix flaky acceptance test.
Fixed studio can't handle more than 9 lines in advanced settings.
STUD-1483
Capture metrics for problem attempts and histograms of problem grades
Fix bad interaction between pluggable InputTypes and Microsites

Pluggable InputTypes use edxmako.paths.add_lookup to inject new
mako template directories. Those were getting clobbered by microsites
(and by theming), which were completely rebuilding the mako template
lookup list from scratch.

This commit switches those two features to use the same add_lookup
function as pluggable InputTypes.

[LMS-2489]
Make new-style chinese language codes works for translation

The old-style chinese language codes used in django 1.4 series are now deprecated, as discussed here:  https://code.djangoproject.com/ticket/18419.
Although majority of browsers still use the old-style language codes, some new browsers such as IE11 in Windows 8.1 start to use the new-style names instead of old-style ones which makes the current chinese translations of edX can't work properly under these browsers.
As there is no easy way for edX to change a higher version of django, I think we could do some mapping here so that the users who use IE11 in Windows 8.1 or other browsers that use the new-style names can view correct translations.
Also, this fix will make users who use one of the language codes:  zh-hk ,  zh-sg  and  zh-mo  can see the correct translations.
Display transcript translations for student in their source language.
Fix acceptance tests.
Wait for big subtitles to render.
Set big timeout for big subtitles.
unicode fixes
line fix
Merge pull request #3162 from cpennington/problem-check-metrics

Capture metrics for problem attempts and histograms of problem grades
Merge pull request #3148 from louyihua/localization-fix

Make new-style chinese language codes works for translation
Instructor- and student-facing documentation for ORA2
Merge pull request #3044 from edx/sylviapearce/documentation/DOC-191

Sylviapearce/documentation/doc 191
Grading Documentation Update

DOC-97
DOC-176

Added note about grading subsections only, and vertical bars
representing subsections in progress tab
Temporarily disable studio acid block tests that are failing