Move AP_Scripting object up to AP_Vehicle

[peterbarker]

Setup for testing was this for each vehicle:

param set SCR_ENABLE 1
param ftp
param set SCR_USER6 17
param set SCR_HEAP_SIZE 222222

... then making sure those parameter values were still present on the new firmware.

[peterbarker]

Board               AP_Periph  blimp  bootloader  copter  heli  iofirmware  plane  rover  sub
Durandal                       56     *           40      40                32     64     32
HerePro             -8                                                                    
Hitec-Airspeed      *                                                                     
KakuteH7-bdshot                48     *           56      56                48     48     24
MatekF405                      *      *           *       *                 *      *      *
Pixhawk1-1M-bdshot             *                  *       *                 *      *      *
f103-QiotekPeriph   *                                                                     
f303-Universal      *                                                                     
iomcu                                                           *                         
skyviper-v2450                                    *                                       

[IamPete1]

This means that scripting now comes up before a bunch of other stuff? What happens if my script needs some of that for its first run? For example it looks like on copter scripting now comes before attitude control and motors. We have singletons for those, so will a script error out on its first run? They can dump you in config error loops also, I wonder what happens to the script in that case.

I think my preference would be to just move scripting to be the last thing init. It means were less likely to hit issues with this change, or in the future if we add more things after where this PR moves it to. I can't immediately think of an problem that would result from having the script come up after stuff its currently before.

[peterbarker]

This means that scripting now comes up before a bunch of other stuff? What happens if my script needs some of that for its first run? For example it looks like on copter scripting now comes before attitude control and motors. We have singletons for those, so will a script error out on its first run? They can dump you in config error loops also, I wonder what happens to the script in that case.

I think my preference would be to just move scripting to be the last thing init. It means were less likely to hit issues with this change, or in the future if we add more things after where this PR moves it to. I can't immediately think of an problem that would result from having the script come up after stuff its currently before.

I've moved it.

[peterbarker]

... I've also done a smoke test to make sure hello_world.lua works on real hardware.