Minor grammar fix.

Fixed a grocer's apostrophe in the Readme.
implementing the subset map ... now to figure out why mine doesn't work right
whoops, need to flip those arguments
need to remove duplicates and sort the results
Okay, got it working completely, I think.
fixing a typo in a comment
implementing the superselector predicate
tweaking this comment
Merge branch 'master' into extend
Finally got this thing to run
Okay, these unit tests seem to be passing.
making the tester easier to use
let's make the brace style consistent
better naming scheme for unit tests
implementing and testing the `paths` function
tweaks
adding the superselector check to the class for complex selectors
working on `superselector` for complex selectors
Merge branch 'master' into extend
implemented `superselector` for complex selectors ... let's hope it's correct