Xcode 9.3 and Swift 4.1 Support

Released on 2018-04-10. All issues associated with this milestone can be found using this filter.

Updated

• All the project copyright headers to use present language instead of end year.
  • Updated by Christian Noon.
• The Xcode project, settings, and Travis-CI file to build and run against Xcode 9.3.
  • Updated by Christian Noon in Pull Request #33.
• The podspec to directly specify swift_version and removed legacy .swift-version file.
  • Updated by Christian Noon in Pull Request #33.

Fixed

• An issue in Xcode 9.3 where NSNumber bridging for Float and Double is no longer implicit.
  • Fixed by Christian Noon in Pull Request #33.