add IO.pipe based on FFI
Merge remote-tracking branch 'origin/master-1.9' into tim/IO.pipe
untag specs for public_send
untag two Symbol#=~ specs
Merge remote-tracking branch 'origin/master-1.9' into tim/IO.pipe

Conflicts:
	src/kernel/bootstrap/Object.rb
Merge pull request #99 from MagLev/tim/IO.pipe

NoMethodError `pipe' for IO