Adding Chinese translation prepared by Liping Chen, MSU
Fix permssions on README
Add "level" to tag widget
Merge branch 'develop' of github.com:openwebwork/webwork2 into develop

Conflicts:
	htdocs/mathjax
Need to escape quote marks in file paths when embedding in html for js.
Added more like this leader tag.
Overhaul OPL-update: reading of tags from problem files is done by the Tags module, support for new tags added, and other simplifications to the code.
Fixed typo in OPL-update
Merge pull request #79 from goehle/merge2.7

Merge2.7
Add Peter's script which pulls OPL taxonomy from the database and stores it as a json object in a file in htdocs.
Merge branch 'develop' of github.com:openwebwork/webwork2 into develop
Provide better solution to the numOfAttempts issue

 Insures that the number of attempts defined in the environment is correct.
 It is the sum of the number of incorrect attempts, the number of correct attempts
 and the number of ungraded attempts (which is 1 or 0 depending upon whether an
 answer has been submitted).
 The calculation is done in PG.pm
Merge branch 'release/2.7' of https://github.com/openwebwork/webwork2 into release/2.7
Merge pull request #80 from jwj61/develop

Updating OPL tag handling
Merge pull request #81 from mgage/release/2.7

Fix off by one bug in number of attempts
Fix disappearing hidden sets.

caused because .hidden was not overriding the display mode for font.hidden
Also fixed the 90% width bug for the problem-content <div>
Merge pull request #82 from mgage/release/2.7

Fix problem-content width=90% bug; Fix disappearing hidden sets.
Define WEBWORK_DIRECTORY if it is not already defined.

Backported from develop
Fixes issue #16
Merge branch 'release/2.7' of https://github.com/openwebwork/webwork2 into release/2.7
Merge pull request #83 from mgage/release/2.7

Define Constants::WEBWORK_DIRECTORY from ENV{WEBWORK_ROOT} if it is not already defined.