Fix spelling of license. Move legalese into a partial.
This allows each institution to have their own licence by simply
overriding the partial
`app/views/curation_concern/base/_legally_binding_text.html.erb`

Fixes ndlib/planning#252
It is also a partial fix for ndlib/planning#230
Merge pull request #167 from ndlib/fix_license

Fix spelling of license. Move legalese into a partial.