Fix compilation issues with icc and g++ < 4.1. Those include:

- conflicts with operator * overloads
 - discard the use of ei_pdiv for interger
   (g++ handles operators on __m128* types, this is why it worked)
 - weird behavior of icc in fixed size Block() constructor complaining
   the initializer of m_blockRows and m_blockCols were missing while
   we are in fixed size (maybe this hide deeper problem since this is a
   recent one, but icc gives only little feedback)

Eigen/src/Core/util/StaticAssert.h

@@ -64,7 +64,8 @@
         unaligned_load_and_store_operations_unimplemented_on_AltiVec,
         scalar_type_must_be_floating_point,
         default_writting_to_selfadjoint_not_supported,
-        writting_to_triangular_part_with_unit_diag_is_not_supported
+        writting_to_triangular_part_with_unit_diag_is_not_supported,
+        this_method_is_only_for_fixed_size
       };
     };