First pass to make subject optional
Added beNil matcher, stability problems when passing non-optionals
expect must be inside it closure, doh
Updated README for optionals
Additional tests for optionals with different matchers
Remove whitespace
Merge branch 'optionals' of github.com:dmeehan1968/Quick into dmeehan1968-optionals

Conflicts:
	README.md
BeNil: add to iOS targets
BeNil: add dedicated spec file
BeTrueSpec: move optional bool tests
EqualSpec: move optional equal tests
ContainSpec: move optional contain tests
Minor style cleanup
Merge remote-tracking branch 'origin'