Revisit the implementation of random_default_impl for integer to make sure avoid overflows and compiler warnings.
Rename map unit test to mapped_matrix: without splitting unit tests, this created a "map" binary file in the include path, not a good idea!

--HG--
rename : test/map.cpp => test/mapped_matrix.cpp
Add no_assignment_operator to a few classes that must not be assigned, and fix a couple of warnings.
Remove double const qualifier