Mavlink terrain protocol support

Added compiler switch for developers to generate survey preset default json files for use as built-in survey presets in custom builds

Support for built-in preset delete prevention

Rework presets

Fix initialization

Pattern Preset support

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

Still a bit buggy

Plus many load/save fixes

- Load/Save working
- Entry point working

Plus new unit tests