Fix XCode error caused by non-unique file names

Swift seems to require files within a module to have unique names. It uses the file names to disambiguate private methods.
Remove Optional:Printable extension for Swift 1.1

It is no longer legal to add public methods to a type defined in another module, according to the error message.
Update tests to compile in XCode 6.1

Tests currently fail due to the removal of the Optional:Printable extension.
Fix output of matched values when tests fail.

A previous commit removed the Printable extension on Optional types, since XCode 6.1/Swift 1.1 does not allow external types to have public extensions.

That extension made output of optionals clearer, and this commit restores that functionalityl.
Merge pull request #35 from nerdyc/xcode61-beta2

Updates to support Xcode 6.1 Beta 2