Start using absolute paths for IO ops
Make chdir slightly less naive. Write tests before elaborating.
Fix chdir and open. Use nqp::readfh and nqp::writefh
IO::Path.contents needs to strip absolutized paths
Change executable name to perl6
IO::FileTestable needs to use absolute paths
Update few methods that were missed.
Merge pull request #202 from donaldh/chdir-emu

Implement chdir emulation for rakudo.