SWC-248: support code preview client-side
do not show code if no preview was available (or if there were any other problems)
use contenttype instead of extension (in most cases)
refactor preview widget, and wrap request builder so that it can be mocked
small refactor
add PreviewWidget tests (and RequestBuilder mock helper)
SWC-248: more work for previews (csv and plain text preview output types)
SWC-248: work for previews
preview work.  fix same-origin policy issue (have filehandle servlet act as a http proxy). fix code extension check
reflect changes in plfm
SWC-451: fix tooltip titles
update zip view, and pom
add zip contents box, with a max height of 200px
from code review with Dave
re-style preview area
merge from upstream
and add new project overview since all of the previous objects shown are now gone
Merge pull request #215 from jay-hodgson/develop

SWC-248: support code preview client-side