Allow user to select dive mode (including PSCR)

[Robert C. Helling]

Hi,



> Am 16.01.2015 um 15:44 schrieb Anton Lundin <glance at acc.umu.se>:
> 
> I completely understand if they are in prefs "for now", but i think they
> should but shouldn't we save these as a "per-dive" ratio?
> 
> 
> As a side-note, I think the o2 consumption should default to something a
> tad higher, about 1000ml or so is probably a good default, and i don't
> know which pscr who have a 1/10 dump ratio, but the rb80 have 1/8 dump
> ratio and my guess is that it and its clones are the most common pscr on
> the market.

As I am not a rebreather diver myself I have no idea what are good defaults. I copied these values from a spreadsheet of s pSCR diving friend. 

Also I don't know how much these values are "constants" for a diver or if they vary dive by dive. 

Another thing: which value do pSCR divers call SAC, the inhaled volume per time or the the consumption of cylinder gas as they differ by the dump ratio?

I noticed some other weirdness with our sac calculation: when we know how only start and end pressures, we interpolate assuming a constant SAC. But it seems the SAC we plot a non-constant sac. 

Best
Robert