Make Profile::DefaultPropertyNames a vector instead of built-in array

A vector doesn't decay to pointer, so we can iterate over it with range-for
in Profile and ProfileReader/Writer without using pointers to array
elements, and a while loop that checks for the special element at the end
of the array to stop the loop. Also remove that dud element at the end of
DefaultPropertyNames.

std::array is a viable option, but the downside is we'd have to specify the
number of elements in it (as that's part of its type), and keeping that
number in sync when adding new properties could be problematic.