Support an overrideable server_url on upload

Allow the options hash to hold a server_url
Write a spec that covers most of upload
Merge pull request #480 from RiotGames/configurable_upload_server

chef_server_url not configurable for upload command
update changelog
update location of berkshelf-vagrant to vagrant-berkshelf
version bump 1.4.1
Use new lockfile
Use new lockfile in the berksfile
Add filepath and fix some errors in lockfile
Read and write cookbook_sources to json
Add new errors for LockfileNotFound
Update lockfile spec and fixture
Fix failing specs in berksfile
Reverse JSON matcher (because it's backwards)
Update lockfile feature and fix filesystem step
Add ref attribute to lockfile for git resources and don't populate empty values
Add OutdatedCookbookSource error
Add legacy support converter for old lockfiles
Add better #to_s and #inspect for CookbookSource
Add #to_s and #inspect to lockfile
Add/Fix update_command features