Move host to class method.

Need this in order to have a single point of entry for override in
ActiveFedora's cleanup method.
Merge pull request #15 from terrellt/feature/HostClassMethod

Move host to class method.
Removed .ruby-version file
Added FedoraLens.base_node
Add ability to set a base_node
Change base_node to base_path
Make sure to look for the path separator when replacing the base_path
uri_to_id should remove the base_path
Translate attribute ids using uri_to_id/id_to_uri
Reload after saving
Clear etag after fetching attributes post create
Encapsulate update/create_and_fetch_attributes
Clear the cached response on an update
use clear cached response to enable loading of changed attributes
Bump dependency on ldp to 0.0.6
Bump version to 0.0.10
Don't push `nil` values into RDF. This is illegal.
It will raise an error when serializing the graph.
See https://github.com/ruby-rdf/rdf-turtle/issues/11
Bump to version 0.0.11
Refactor so that Core can be used without including ActiveModel
This enables ActiveRecord to include FedoraLens::Core onto
ActiveFedora::Base without inadvertently pulling in ActiveModel includes
which mess up the ancestor chain.
Prepare for version 0.0.12