Smaller ExtJS 4.2 jar

Update to https://github.com/webjars/webjars/issues/86
Update pom to filter out unneeded resources.  Brings the final jar size down from 69MB to 13MB

Also the previous appoach of unzip them move took 40 mins to run on my terrible work PC.  A blame the virus checker.  The new approach of using exlcudes filters stripping the leading path on copy, takes only 2 mins to run.