Updated linux binaries to fix libpng support (helps #89).

Binaries have been updated to use whatever system libpng library is
available (without being linked against a particular version).

This also includes fix for 64bit systems to allow for these binaries to
work with "older" versions of libpng (for example, v1.2).

The binaries include wxwidgets fix for lsb_release messages, so the
workaround for this issue has been removed.