deprecate chef_api and site from the Berksfile DSL
add 'source' to Berksfile DSL for adding Berkshelf api sources
add Berkshelf::APIClient for communicating to API Servers

an API server will now start and run with no builders started during the test suite
you can add to the cache with the helper methods included by Berkshelf::Rspec::BerksAPIServer
resolver will now build and read a universe to determine a solution
fix issue where all locations were not required properly
add Berkshelf::Source
move installation logic into Berkshelf::Installer

Berksfile#install will instantiate an installer and run it
Initial pass for installing scm based dependencies
Initial pass for installing dependencies defined by the Berks API in a Chef Server or on the Community site
remove chef_api locations from dependencies

this is now replaced by a source that contains a chef server cache builder
remove downloader from berksfile
refactor locations to inherit from Location::Base

dependencies either have an explicit location or they have none
remove site locations
don't assume 'cookbooks' uri segment is included in community uri
only include a location if it is present in use messages
fix failing Berksfile tests
fix api client specs
fix community rest specs
fix failing dependency specs
fix graph specs