getopts missing docs
auto merge of #12942 : alan-andrade/rust/docathon-getopts, r=alexcrichton

https://docs.google.com/spreadsheet/ccc?key=0An9tLRVf1SSfdE9jX1Q2QkhiUGVwTnh5YTJnMHVUYXc&usp=sharing#gid=6