parse-xml.c: add parsing for DivingLog divetime and depthavg

I have a sample file where the time is given as minutes.seconds instead of
minutes:seconds.

Fixes #69

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Updated bg_BG translation

- missing strings from parse-xml.c
- translation for "No Events"
- small uppercase fix

Signed-off-by: Lubomir I. Ivanov <neolit123@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>