u_wip
make tests pass
merge master, make tests pass
Merge pull request #90 from escherba/u_wip2

make tests pass
do not create unnecessary copies of lists
make eggs not wheels
Merge pull request #91 from escherba/u_wip2

do not create unnecessary copies of lists
fewer assignments in often-called function
add comment
Merge pull request #92 from escherba/u_wip2

minor optimization
Merge pull request #22 from escherba/master

make eggs not wheels