Many changes in how we're presenting the NSString APIs on String, most
notably that we now traffic in String.Index and Range<String.Index>
rather than Int and NSRange. Also we present NSString initializers that
can fail only as factory functions, and factory functions that can't
fail only as init functions.
About 25% of the API changes here have been reviewd by the Foundation
guys, and testing is, as it has always been, admittedly spotty. Dmitri
is going to be writing some more comprehensive tests.
Swift SVN r18553
String interpolation invokes convertFromStringInterpolationSegment() function
now. There is no need to add extensions to String to allow custom types to
participate in string interpolation. Just implementing Printable will do the
right thing.
Swift SVN r18104
