started changing ExGraph type
somes changes to loops parsing
changed tograph, again
loops improved
funcs now working on for loops, starting reversegraph..
changes
improved simplify, fixed reversegraph, testing for loops
started rev on NFor
I hate loops
repairing NSRef derivation
repairing NSRef derivation 2
for loops looking better
fixed setindex derivation, started on for loops pruning
fixed prune on loops
fixed deriv NSRef, tested some loops
removed isequal(ExNode, ExNode) defiition, switched back to Base.in() definition
parents field declared as Vector{Any} to avoid convert errors
started modifying for loops derivation
loop derivation modif complete, some tests pass
for loops looking better, inactivated node fusion