Fix a bug in MultipleDatabaseModelDocument

An instance of a MultipleDatabaseModelDocument-derived type could forget
its Mongo collection name under some circumstances. The MongoEngine
metaclasses assume that a newly created object's class metainformation is
stored in 'meta'. The metaclasses then move the metainformation to '_meta'
for the object instance. This moves the metainformation from '_meta' back
to 'meta' when copying a MultipleDatabaseModelDocument.
Merge branch 'multipledatabasemodel_bug'

* multipledatabasemodel_bug:
  Fix a bug in MultipleDatabaseModelDocument
Clean some whitespace
Revert "Allow import for slideatlas without mongodb"

This reverts commit 46fdad290f912c0db9fe04277f345e87799e24e5.
Require the Flask app to be created explicitly

Simply importing the slideatlas module will no longer implicitly create
a new Flask app. This provides more control over when the app is
instantiated.
Don't attempt to make a database connection when generating documentation

Fixes #42.
Merge branch 'documentation_config'

* documentation_config:
  Don't attempt to make a database connection when generating documentation
  Require the Flask app to be created explicitly
  Revert "Allow import for slideatlas without mongodb"
  Clean some whitespace
Image inheritance will not work with image databases as of now
Merge branch 'fix/image-viewaccess'

* fix/image-viewaccess:
  Image inheritance will not work with image databases as of now
Fixing TILELOADER
Fix bugs in URL generation for stack viewer
Merge branch 'stack_view'

* stack_view:
  Fix bugs in URL generation for stack viewer
Merge remote-tracking branch 'github/master' into dev/dj-searchbox

* github/master:
  Fix bugs in URL generation for stack viewer
  Fixing TILELOADER
Resync and Sync operations work if no file is deleted
Merge branch 'fix/resync-no-delete'

* fix/resync-no-delete:
  Resync and Sync operations work if no file is deleted
Fixes getview by creating two fields .. this needs a review
Merge branch 'fix/getview'

* fix/getview:
  Fixes getview by creating two fields .. this needs a review
Wesocket transport selected only after successful handshake, until then fallback to http
Merge branch 'fix/websocket-still-connecting'

* fix/websocket-still-connecting:
  Wesocket transport selected only after successful handshake, until then fallback to http
Use canvas by default (not webGL)