Create 2012-11-19-ns_enum-ns_options.md

Translated on the train from Tainan to Taipei.
Merge branch 'zh-Hans' of https://github.com/NSHipster/articles into zh-Hans
update according to reviews
Merge pull request #120 from croath/zh-Hans

Create 2012-11-19-ns_enum-ns_options.md