Cleanup the snapshots feature a little

This is mainly meant to fix the case where webserver_user isn't configured.
Since we don't enforce it to be defined, it seems silly to rely on it.
Merge pull request #49 from ss23/webserver-cleanup

Cleanup the snapshots feature a little
Fixing bug where SyncProjectsAndEnvironments failed on undefined method

DNProject::DNEnvironmentList() returned the wrong type of list, because
filterByCallback changes it to an ArrayList.

The whole thing of overloading the static get() on DNEnvironment and
DNProject to return a specific DNEnvironmentList or DNProjectList
seemed prone to error, so I've removed that and refactored the sync
and remove obsolete methods onto SyncProjectsAndEnvironments. It seems
like they belong here anyway, not on the lists themselves.
Merge pull request #53 from halkyon/dnenvironmentlist_bug

Fixing bug where SyncProjectsAndEnvironments failed on undefined method