Correctly computer O2 partial pressure

I had forgotten a / 1000.0 in the conversion of partial pressures from (double) bar to (int32) mbar.

Fixes #763

Signed-off-by: Robert C. Helling <helling@atdotde.de>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Small changes to Yearly Statistics window

Added a title bar with close button.
Set an appropriate title.
Centred the window relative to mainwindow.

Signed-off-by: John Van Ostrand <john@vanostrand.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Prevent garbage from being saved in the userid field

It seems that in some scenarios we end up with a string that isn't NUL
terminated and that results in garbage being stored as userid. This patch
is a little brute force but it fixes the problem even if a previous
version os Subsurface ended up adding other text to the end of the userid.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Adjust Poseidon Mouth piece event strings

After some feedback on the mailing list, these strings where preferred.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
De-obfuscated Poseidon gaschange event building

After some feedback on the mailing list, bitwise XOR wasn't the
preferred way to build the gaschange event.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>