Merge pull request JohnSundell#56 from KieranHarper/xcode-folder-mapping

Groups for Sources and Tests

Optionally infer project name, author name + email & GitHub URL

SwiftPlate will now use information available from the file system and git
to infer most settings. These are still user overridable, but in case the
user leaves them blank the inferred information will be used.

Merge pull request JohnSundell#33 from codeOfRobin/master

Added --force

README: Document command line arguments

Refactor argument processing code to be more in line with rest of Swi…

…ftPlate

- Use guard statement to validate array index.
- Use initializer for Arguments instead of global function.
- Fix bug where camel cased argument identifiers where compared against lowercased ones.
- Update some variable names & code style.

Linux: Minor code formatting fixes

Merge pull request JohnSundell#14 from MarvinNazari/master

Added option for organization name