port LUDecomposition(base + alt) to AltLU
add lu decomposition base tests
add lu decomposition alt tests
port LinearSolverLU to LUSolver
add tests for LUSolver
Merge branch 'develop' of github.com:mikera/vectorz into lu_solver
add least squares for AMatrix in API
return null when no solution, add API tests
add docs
Merge pull request #57 from prasant94/lu_solver

Lu solver + tests
Tidy test code
tidy imports
factoring and docs
docs and simplification
refactor setElements with extra target position argument
improve setElements range checking
optimising dense array copying
tidying etc.
better setElements fro strided vectors
refine setElements