update spec to reflect node impl
Merge pull request #18 from poptip/spec2

Update spec to reflect node impl.
Initial work on a golang port of Variants
More features, testing, and visibility changes.
README, final API changes.
Actually adding the file.
Update spec, require operator for >1 condition.
Low-hanging comments
nil check on condition evaluator
added todo about bad inputs
some cleanup
Merge pull request #19 from poptip/feature/golang

A golang port of Variants