mobile planner UI

[Rick Walsh]

This series adds a basic UI for cylinder editing and a dive planner. It needs to be connected to the core planner code before it actually plans a dive.

Hopefully the cylinder edit page is useful beyond just the planner.

This is not ready for use, and should not be included in the first stable release. With a bit of luck, people who understand Qt and c++ better than me will help turn this into something functional. Or at least trigger a bit of discussion.

The main steps I see to make the planner functional are:
1) Use Qt models rather than qml ListModels - I might be missing something, but it appears the existing QAbstractTableModel / CleanerTableModel used for the existing tankinfomodel and diveplannermodel don't play nice with qml.
2) Connect with core planner code via Qt

Beyond that, we want some essential preferences/features to make it useful for real dive planning.  In rough order of priority
- Gradient factors
- SAC (along with UI to report gas usage)
- Imperial units

Other useful features/preferences
- consider deco loading from previous dives
- save plan as dive

A few others that are lower priority
- Altitude
- Salinity
- custom ascent/descent rates
- last stop depth
- report CNS and OTU
- CCR
- VPM-B, with conservatism
- Minimum switch duration
- O2 breaks
- Display transitions in deco

Cheers,

Rick