This is ridiculous.
If you develop on a mac, you must download dash, now.
It allows you to keep an offline copy of docs, and makes them all searchable from the same interface (very fast).
You can even integrate with Sublime, and push CNTRL+H over a word to look it up in dash.
50% of development is looking up docs. This is a game changer.
I just installed offline docs for..
All from one interface. Really awesome.