Initial feasibility proof

Sort of a mock-up.

There are four controls: Range, Gain, Sea, Rain.
Press them and the display changes into Edit mode for that control.

Nothing is really wired up yet, the only thing that this does is show
the controls.
Issue 25 phase 2 - major controls wired up

Range, Gain, Sea, Rain, Transparency and Rejection are now wired in.
The edit controls control the values, and these are transmitted back
and forth to the main plugin class.

Visually this is OK, but it has not been tested yet with a real radar.
Process feedback given by @Atlantic42.

- Rename rejection to "Interference Rejection" (abbreviated to "Interfer. Rej" like HDS).
- Add names Off/Low/Medium/High for interference rejection.
- Rename "Sea" to "Sea Clutter" (like HDS).
- Rename "Rain" to "Rain Clutter" (like HDS).
- Send commands to radar when a control is changed other than range.
- Continue to improve logging in verbose mode.
- Fix max value 10 for transparency.
- Hide Auto button if it is not to be used
More work on issue #25. Wire up guard zones.

Adds "Guard Zone 1" and "Guard Zone 2" buttons.
Also includes work to allow dual guard zones active at the same time.
Fix range display and calculation.
Version 0.40511 for controls v3 rewrite
Fix gain and sea clutter range

Values 0-100 were transmitted to the radar unchanged, but they should be scaled to range 0-255.
Fix alarm zone editing.

The wrong alarm zone was selected, easy fix.
To make it easier to work on the alarm zones, they are now also displayed
if the radar is asked to transmit but no radar is on the network.
Fix display of the AlarmZone dialog on MSW and OSX.

On OS X the size is no longer 0 by 0 but best fit. On OS X, SetSize(0, 0) actually works!
On MSW the size is no longer 260 wide but best fit.
Add Target boost control.
Move three controls to an advanced 2nd layer menu.

The following three controls are now one level down, to control the size of the top level menu.

    Transparency
    Rejection
    Target Boost
Only draw radar image if it has just been received.
Version bump
Change +1/-1 to +/- buttons

As some values are not increased by 1 or decreased by 1, remove the number.
Merge pull request #28 from canboat/controlsv3

Fix #25 - Rewrite controls to be more compact
Merge branch 'master' of https://github.com/canboat/BR24radar_pi