first iteration of mission stats calculation (dist and maxTelem)

add survey item distance to mission distance

remove unused calculations from _calcHomeDist

added correct calculation of missionMaxTelemetry when there is a complex item

use speed to compute mission time according to vehicle type

started implementation of hover and cruise distance

corrected typos

added logic

prevent survey from crasing

added checks for vtol

rearrange logic

added primitive check for landing

rearranged checks

new arrangement

added logic for transition

fix for small bugs

add check for mission speed larger than 0

remove already existinh check

reduce code a bit

clean up

Affect on grid is to specific to details of polygon to test

Vehicle change: All items removed
Vehicle add: Request sync is not already in progress

Instantiating QSettings on the stack is quite expensive (full file read+parse each time) and this was done in a tight loop with mission items as they were dragged. Very slow.