let clang-tidy provide default member initializers (#562)

let clang-tidy provide default member initializers (#562)

* let clang-tidy provide default memeber intializers

This is the check cppcoreguidelines-pro-type-member-init, but
it was only applied to the class declarations for our filters,
formats and vectors.
This is currently irrelevant as all these are constructed globally,
but if one constructs dynamic instances errors can be seen in gpx, kml, nmea
and lowranceusr formats.

* revert filter_vecs change which MSVC 2015 choked on.