Add ContentType constants in WebContent.  Use as much as possible.

git-svn-id: https://svn.apache.org/repos/asf/jena/branches/jena-fuseki-new-ui@1553008 13f79535-47bb-0310-9956-ffa450edef68
Remove temp file

git-svn-id: https://svn.apache.org/repos/asf/jena/branches/jena-fuseki-new-ui@1553009 13f79535-47bb-0310-9956-ffa450edef68