Improve install section in README
Minor improvements.
Fix preview bug.
Remove debug code
Handle XQST0033 like DuplicateNamespace
Merge pull request #2663 from ulikoehler/master

Improve readability of Install section in README
Merge branch 'master' of https://github.com/ajaxorg/cloud9
Merge branch 'master' of git://github.com/wcandillon/cloud9
Merge branch 'master' of git://github.com/ldoblies/cloud9