Fix MSVC warnings in tests

[MarcelRaad]

MSVC complains about narrowing conversions and unreferences parameters.
This makes all tests almost level 4 warning clean on MSVC 14.

[Flast]

std::begin/end is came from C++11, so I think those should be replaced with boost::begin/end.

[MarcelRaad]

Rebased and removed the two commits which are already integrated. Only the warning fixes are left now.

[mclow]

IIRC, the unsigned in hex is there to prevent warnings on other compilers.

[mclow]

In the testX checks, I'd rather change dest to a size_t, since that's what std::distance returns.

[MarcelRaad]

IIRC, the unsigned in hex is there to prevent warnings on other compilers.

OK, I reverted that one.

In the testX checks, I'd rather change dest to a size_t, since that's what std::distance returns.

Right, that's better! It's ptrdiff_t rather than size_t, but it also applies to the operator+ used in the other tests. I changed that now.