Added some logic so it can handle multiple Github configurations

With this added logic you can use multiple Github organizations and/or
Github Enterprise organizations. This code doesn’t change the default
behaviour, but it does change the github config section from being a
string with a single entry (access_token), to an array with one (just
the one ‘access_token’ entry) or several entries (depending on your
config/setup).
Updated default value to match new type
Standardize on CookbookNotFound errors

Fixes #1041
Standardize on DependencyNotFound
Move DuplicateDependency error text into errors.rb
Move InsufficientPrivledges error text into errors.rb
Move CommunitySiteError error text into errors.rb
Remove unused error classes
Standardize on what an error looks like
Fix failing cuke
Remove Berkshelf:: prefix on errors
Use quotes instead of weird backtacks
Added location_type :uri

This allows berkshelf to download gzipped tarballs from arbitrary urls.
Bump Ruby development version [ci skip]
Add lifecycle command for bumping the local version
Only compare the URI#host for checking locations
Merge pull request #1065 from berkshelf/sethvargo/more_solving

Add lifecycle command for bumping the local version
Merge pull request #1064 from docwhat/url-downloader

Added location_type :uri
Merge pull request #1045 from svanharmelen/Add-logic-to-work-with-multiple-github-configs

Added some logic so it can handle multiple Github configurations
Merge pull request #1051 from berkshelf/sethvargo/better_errors

Improve errors