upgrade to guava 17.0.

It has the jsr305 (javax.annotations) dependency as transitive
now so we have to declare it explicitly.
This is mainly to coordinate the dependency version with downstream projects.
Merge pull request #256 from groldan/upgrade_guava_17

upgrade master to guava 17.0.
Revert "upgrade to guava 17.0." until geoserver upgrades.

This reverts commit 4de7ffcd3253dd4043f44a97d4f24409e026a14f
in order not to cause a compile error on geoserver master due
to guava 17 being dragged as a transitive dependency and override
geoserver's version.
The patch can be re-applied once geoserver upgrades to guava 17.0 too.
Re-apply "upgrade to guava 17.0.". geoserver upgraded.

This reverts commit f820c83ed4951547ed35bcdd88d11d330dd80ccb.
Merge pull request #258 from smithkm/dq-namelength

Upped layer_name in DiskQuota JDBC to 128 char
Document Disk quota layer name size limit