Prefer Guava Files over FileInputStream

This ensures proper resource handling.
JCLOUDS-546: Remove Javadoc @author annotations

Annotations removed with:

find -name \*.java | xargs sed -i /@author/d

Empty Javadoc removed with multiple iterations of:

find -name \*.java | xargs sed -i -z 's/ \*\n \*\// \*\//'
find -name \*.java | xargs sed -i -z 's/ \* \n \*\// \*\//'
find -name \*.java | xargs sed -i -z 's/\/\*\*\n \*\/\n//'
Address Checkstyle violations
JCLOUDS-458: GCS skeleton with authentication
JCLOUDS-458: Added Default object access control
JCLOUDS-458: Add BucketAccessControls

This commit includes expect tests but needs not-yet-implemented bucket
operations to implement live tests.
Added the CONTRIBUTING file
JCLOUDS-458: Add Bucket Operation with live tests
JCLOUDS-620: Don't fail on tag filtering when group is not specified.

Follow-up from 69756496
Fixing other Checkstyle violations in GCE.
[JCLOUDS-550] fix for obsolete machineTypes