Merged ModelBase from devmo and sumo apps and get rid of cache machine.

This is an important step to have a leaner caching setup.
Added new "memcache" caching backend to be used by Jinja2 and constance.

Removed settings_local.py based CACHES setting in favor of settings.py.
This requires an update of all local_settings.py in use!
Move PageMoveError into exceptions module.
Extended render_stale_documents task to use a task group for its subtasks.

That means we can set a lock at the start of the task and destroy it again once the whole bunch of tasks have finished.
Added a MemcacheLock utility.
Use memcache cache backend for the rebuild task.
Merged the obscure lib/utils.py with devmo.utils.
Fixed the tests for the rebuilding of documents.
Stop deprecation warning to show up.
fix bug 1015270 - urlize to link urls in soapbox
Be quieter when unpacking the wheelballs.
Use puppet module to install elasticsearch.
Updated feedparser to latest version to fix UnicodeDecodeErrors with feeds that contains Unicode content.
Merge pull request #2424 from groovecoder/soapbox-links-1015270

fix bug 1015270 - urlize to link urls in soapbox
Remove Rackspace, Vmware and EC2 Vagrant integration. Untested and not well maintained.
Use a newer version of Vagrant and install the vagrant-vbguest plugin to keep the guest additions up-to-date.
Run apt-get update before installing some packages.
Make sure the node binary is even there.
More changes with regard to other Vagrant providers.
Remove old scripts.
Remove old migration that has been superceded by constance's own migrations.