dlist
merge 'undoredo' into 'dlist'

Conflicts:
	src/lib.rs
	src/main.rs
visibility
option -> x, treemap -> hashmap
something
nailed it
i64 -> Revision
fully persistent dlist
dlist
visibility
option -> x, treemap -> hashmap
something
nailed it
i64 -> Revision
fully persistent dlist
Merge branch 'dlist' of github.com:zaic/negative into dlist