added chain_syntax.rs and once_closures.rs
updated readme

added explanation and usage information to readme for chain_syntax and
once_closure
Merge branch 'master' of https://github.com/jessopher/rust-goodies

Conflicts:
	README.md
idk. I am not used to git. But I made some changes to to the readme via
githubs web interface, and apparently it conflicted with changes made
locally. This should fix it.