Remove trailing whitespaces

Most of them appear in the disclaimers, but some are in the code as
well.
Cache the gas mix data internally.

The gas mix data is used from multiple functions, and the code to parse
that data is duplicated in each function. Because this is error prone,
the code is moved to a single place, and the data cached in the parser.
Report the initial gas mix.

The Suunto dive computers record gas change events in the profile data.
But because there is no gas change event stored on the first sample, the
application doesn't know which gas mix is in use, until the very first
gas change event occurs.

For the Suunto HelO2, the index of the initial gas mix is stored in the
dive header. This is most likely also the case for the other models, but
I haven't found yet where exactly it is stored. As a temporary solution,
we simply assume the initial gas mix is the first gas in the list with
available gas mixes. This should be a reasonable assumption for most
dives.

Fixes ticket #2
Merge branch 'suunto'
Fix building for Android

This makes libdivecomputer build via Android NDK. Its currently unusable
due to the fact that Android usually doesn't provide any kernel serial
drivers.

Signed-off-by: Anton Lundin <glance@acc.umu.se>