strings: ToTitle works as ToUpper instead of capitalizing

[sanatgersappa]

Looks like a regression of #933.

See http://play.golang.org/p/27QjEvE6nC

Tested on Go 1.4.2 (windows/amd64)

[minux]

http://golang.org/pkg/strings/#ToTitle

ToTitle returns a copy of the string s with all Unicode letters mapped to their title case.

[sanatgersappa]

Sorry, my bad. Found that Title() does what I need.