Initial code to import CSV log files

This patch implements basic functionality to import CSV formatted log
profiles to Subsurface. The import includes time, depth and temperature
from AP Logviewer based on one sample log file I have received. It is
assumed that dive time is the first parameter and depth second.

Temperature is given as a parameter from C source (hard coded currently
to field 15) but we should have a GUI implemented for selecting the
wanted fields.

The two different sample logs of CSV dive log export I have received use
tabulator as field separator. I assume the possible GUI should have
option for the FS as well to be given as parameter to the XSLT.

[Dirk Hohndel: small fix to the error string malloc]

Signed-off-by: Miika Turkia <miika.turkia@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>