Merge pull request #50 from PatrickDropbox/master

add more comments on how dropbox uses the memcache package.
Merge pull request #51 from PatrickDropbox/master

add IsLocalhost utility function + go fmt
Add HasKey checker to gocheck2
Merge pull request #53 from adegtiar/add_haskey_checker

Add HasKey checker to gocheck2
Implement a SingletonFactory
Merge pull request #56 from teisenbe2/singleton

Implement a SingletonFactory