Working.on.lu.using.ffpack

example:
```

loadPackage "FastLinearAlgebra"
debug Core
R =  ZZp(101,Strategy=>"Ffpack")

m = mutableMatrix matrix{{1_R,2_R},{4_R,6_R},{3_R,4_R}}
 LUdecomposition m

m = mutableMatrix matrix{{1_R,2_R},{4_R,6_R},{3_R,4_R}}
(P,Q) = rawLQUPFactorization(raw m)
```