Using "index" instead of "size_t" in "Dump.cpp" to avoid warning

The warnings now should be gone - imho there is no pretty solution for this whole thing as boost's "index" is a black box type which thus shouldn't be used with own arrays / types at all. That however would (in this case) mean to iterate over a 2nd set of own-type vars (and use those instead of "index" where required).
Long story short, I chose to cast instead - might not work in future if the boost team makes "index" some weirdo type.