This provide several advantages:
- more flexibility in designing unit tests
- unit tests can be glued to speed up compilation
- unit tests are compiled with same predefined macros, which is a requirement for zapcc
- Replace internal::scalar_product_traits<A,B> by Eigen::ScalarBinaryOpTraits<A,B,OP>
- Remove the "functor_is_product_like" helper (was pretty ugly)
- Currently, OP is not used, but it is available to the user for fine grained tuning
- Currently, only the following operators have been generalized: *,/,+,-,=,*=,/=,+=,-=
- TODO: generalize all other binray operators (comparisons,pow,etc.)
- TODO: handle "scalar op array" operators (currently only * is handled)
- TODO: move the handling of the "void" scalar type to ScalarBinaryOpTraits
- remove most of the metaprogramming kung fu in MathFunctions.h (only keep functions that differs from the std)
- remove the overloads for array expression that were in the std namespace
added function for array.min(), array.max(), matrix.cwiseMin(), matrix.cwiseMax().
The matrix.cwiseMin/Max functions required the definition of the ConstantReturnType typedef.
However, it wasn't defined until after MatrixCwiseBinaryOps was included in Eigen/src/SparseCore/SparseMatrixBase.h,
so I moved those includes after the definition of the typedefs.
tests for both the regular and scalar min/max functions were added as well
