Complete rework of global math functions and NumTraits.

* Now completely generic so all standard integer types (like char...) are supported.
** add unit test for that (integer_types).
* NumTraits does no longer inherit numeric_limits
* All math functions are now templated
* Better guard (static asserts) against using certain math functions on integer types.

Eigen/src/Array/ArrayBase.h

@@ -54,6 +54,8 @@ template<typename Derived> class ArrayBase
 #ifndef EIGEN_PARSED_BY_DOXYGEN
     /** The base class for a given storage type. */
     typedef ArrayBase StorageBaseType;
+    
+    typedef ArrayBase Eigen_BaseClassForSpecializationOfGlobalMathFuncImpl;
 
     using ei_special_scalar_op_base<Derived,typename ei_traits<Derived>::Scalar,
                 typename NumTraits<typename ei_traits<Derived>::Scalar>::Real>::operator*;