Add chinese language  zh_CN.po
Add chines zh_CN.mo file
Merge pull request #67 from mgage/release/2.7

Add chinese language  zh_CN.po
Merge pull request #69 from goehle/upgraded2.7

Backports of Bugs
Merge pull request #70 from goehle/upgraded2.7

Fixed problem with Select All buttons
Fix label position: put problem numbers BELOW bars in the bar graph
Merge pull request #71 from paultpearson/release/2.7

Fix label position: put problem numbers BELOW bars in the bar graph
Merge branch 'release/2.7' of https://github.com/openwebwork/webwork2 into upgraded2.7
Fixed missing messages