nodes must have at least one item
better List1 definition
Merge branch 'master' into invariants

Conflicts:
	Data/Spine.hs
fixed problems due to rushing
got it to compile using List1 for Nodes
added List2
better strategy for List1/List2; embedded length assertions in the code
cleanup
began parser
updated to use unquotesplicing; sacrificed List1
finished parser draft
fixed a functor bug in QuaisSpine
comments; more parameterizability in QuasiSpineParser class; better parser api