update tests, mostly to use api calls instead of construct objects manually. set next ptr to null in list_pop_head
WIP: update tests (&minimally code) for prev pointer in node
tests passing
rm gigo case & need for stoopid if
+test for release on failed insert
cleanup
rm unnecessary code
fix documentation
address mdl comments on PR
condense code
remove commented out code & notes
add asserts
Merge pull request #28 from abellenir/list_double

Double-Linked List