readme updates
optimize draw map
oops ... bug in that last optimization
gridClr doesn't need to be static
turn index into running sum

(first pass)
optimize drawing selection line (beta)
Make sure vOff always defined
calculate b only once
remove unnecessary variable l
simplify selection lines calc
don't calculate entire selection line
reduce number of comparisons
redundancy
rem var e
condense
reduce testing
condense
simplify max depth calculation
a vxeing problem with first split
indexing +1 shenanigans