Added better error messaging/display to DynaTable.  Since we removed the static resource code, it's now much more likely for server calls to fail (when serving from a file system, for example).  So it's important the error dialog be very helpful.

Patch by: jlabanca, me
Review by: jgw


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@1334 8db76d5a-ed1c-0410-87a9-c151d255dfc7