Require confirmation before arming / making the drone take off

[m4gr3d]

A prompt should show when the user click on the arm, and on the take off button, to ensure that they were not clicked on accidentally.

[arthurbenemann]

@jason4short Comments?

[arthurbenemann]

[m4gr3d]

that prompt would be great!

[m4gr3d]

if we decide to add a prompt to the take off button, the second paragraph can be moved there instead.

[arthurbenemann]

From a chat at G+, it seams that even more important is a disarm button

[Thalek]

I concur. If you're going to be able to arm the drone from the software, you're going to need to disarm it afterward.

[keyoss]

+1 a disarm button is really important

[arthurbenemann]

@ne0fhyk The dialog added by #1106 doesn't seam as intrusive as I thought it would be.