Xcode lulz
Refactor `update` command to use `checkout`
Fix docs and visibility in build command
Refactor `bootstrap` command to use UpdateOptions
Hide ProjectEventSink in Checkout implementation
Spaces -> tabs in Version
Don't display version in `carthage help version`
Prettify `carthage help` list a bit
Use consistent function descriptions
Separate argument usage by a blank line
Include default value in help, clarify booleans
Hopefully clearer help for --skip-current
Hopefully clearer help for --configuration
Clean up code branch for --no-key vs. --key
Revert "Clean up code branch for --no-key vs. --key"

This reverts commit 73f6c1bf0e9a19e01afd117d62024b863e38eae6.
Use a ternary for defaultValue
Merge pull request #117 from Carthage/command-improvements

Improve Command implementation and user-visible help