Fix typo in con-student that broke problem load.

Fix up some indenting.
Merge branch 'master' into jingxian2
Merge branch 'master' into jingxian2
The file dojo-install-version should *not* be in git.
Use "git commit -a" or "git add" to avoid this kind of
error.  Don't use "git commit ." and the like.
Rename Undo button to "Clear" in algebraic editor
Merge branch 'master' into jingxian2
Code review for renaming Undo button.