fill Var class
deep commutativity/associativity
bump version number
deep associative/commutative unification

Create relations commutative and associative
Use conde to branch between them deeply within an expression
add single eq_assoccomm external goal
__all__ for assoccomm
move iter utils to util.py
add output to corleone example
update REAME from blogpost
Update README.md

added example showing that asking for more values of x than satisfy the given expressions returns all values that satisfy the given expressions
Merge pull request #9 from jdmcbr/patch-1

Update README.md
add commutative example
rename variables in appendo
change `u is v` to `u == v` in unify
add states example
add comments to state example
simplify state example
add FL-TN example
move util tests to test_util.py
bump version number
fix state abbreviations