Add public accessors for types... (XCode 6b4)

This is the first step in getting Quick ready for XCode 6 beta 4.  Note
that Nimble-OSX is still failing to compile with a message of "using
bridging headers with framework targets is unsupported".
Add public accessors for global DSL functions
Update Nimble reference to latest commit.
Merge pull request #99 from drmohundro/master

Add public accessors for types to begin supporting XCode 6 beta 4.