Changed the location_path so it contains the full repo URL

This extra info is needed by the berks command when downloading the
cookbooks from Git based on the given API info. Without this extra info
it’s impossible to determine which Github location should be used (when
using multiple organisations and/or Github Enterprise organisations)

This change needs to be merged in correlation with
berkshelf/berkshelf#1045
add build-essential to cookbook
include gemspec in package
update README with cookbook installation instructions
version bump 1.2.1
bump cookbook's lockfile
set log level of Celluloid to ERROR
upgrade reel dependency
Merge pull request #88 from svanharmelen/extend_location_path

Changed the location_path so it contains the full repo URL
Merge pull request #102 from berkshelf/upgrade-reel

LoadError: cannot load such file -- http/headers
version bump 1.2.2
fix dependency conflict with celluloid-io 0.16.0.pre
bump berksfile lock
add attribute documentation to cookbook README
Merge pull request #103 from berkshelf/update-cookbook-docs

add attribute documentation to cookbook README
add warning messages when a github or file_store cache builder is started
Merge pull request #104 from berkshelf/warn-builders

add warning messages when a github or file_store cache builder is started
bump octokit constraint
version bump 1.3.0
bump lockfile