Add L1-norm to core cpp lib, py. and matlab wrappers. Also add unit tests for...

Add L1-norm to core cpp lib, py. and matlab wrappers. Also add unit tests for this norm for py. and matlab.

New functions in cpp lib:
- Faust::MatGeneric::normL1(), Faust::MatGeneric::get_col() (implemented in MatSparse and MatDense),
- Faust::Vect::normL1(),
- Faust::Transform::normL1() and binding Faust::TransformHelper::normL1().