We can instead 'Open' these files as they are just bastardized XML files.
This gets us back to a more consistent point where 'Import' gets data
directly from the dive computer (and hopefully soon we will add the
ability to load a dive directly from a uemis SDA to libdivecomputer),
and 'Open' loads a file from the filesystem of the computer we are
running on (this last sentence phrased so awkwardly as the uemis Zurich
SDA is a computer and presents a file system when connected via USB - it
just doesn't have the dive data in an accessible format in that file
system).
As a bonus we get to throw away quite a bit of code (the uemis specific
file handling, mini-XML parser with helper functions, the file open dialog
in the importer). Yay!
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>