Adds newer version of surefire to pom.xml to make testing easier.
Adds workaround for cacheing bug

- Subsequent GC requests on netcdf files result in a null feature type
  being returned. It was determined that the request cache was causing
  the state of the netcdf dataset objects to be altered in such a way to
  cause the feature type to be null.
Updates snapshot
Merge pull request #97 from lukecampbell/cachebug

Adds workaround for cacheing bug