Merge pull request #286 from scidom/master

Added C::PtrDiffT alias and did housekeeping of C types
Small fix in HTTP::Client, and added some typeof specs.
Set default whence in FileDescriptorIO#seek to SEEK_SET.
Merge pull request #289 from mverzilli/master

Set default whence in FileDescriptorIO#seek to SEEK_SET.
Added String#split(separator : Regex)
Merge branch 'master' of https://github.com/manastech/crystal
Merge pull request #290 from mverzilli/master

String#split(separator : Regex)
Setting up Stats module