initial attempt at using the explicit merge. (broken)
closure to working merges. works for small test cases
tally bugfix fromList4
working explicit merge, but it is 3-4x slower than the fusion-based merge
insert4 is faster than a simple insert, but the heap overhead is too high
bound fix
proper tally is possible now with better bound
INLINE merges goes a long way towards rectifying the speed imbalance
inlining a litte more
insertDistinctAscList
Merge branch 'explicit-merge'. Using explicit-merges for insert4 for comparison.

Conflicts:
	src/Data/Vector/Map.hs