Fix multi-button commands

[Noel215]

Hi,

With the current implementation, the multi-button commands are executed if any of the buttons defined is pressed.
I expected the execution of the command if and only if all the buttons are pressed at the same time.

I've added a patch and a test to check the behavior in that situation.

[bmagyar]

thanks!

[sprhawk]

@bmagyar I don't understand why approved this change

if I set buttons 1, 2, 3, only if all these buttons are pressed at the same time, self.active == True, then the topic will be sent. I don't think this is the normal case.

And the check:

self.active &= joy_state.axes[axis] == 1.0

Is the axis used as a button ? The statement means only when axis is in max (1.0), self.active == True, then the topic will be sent. (not the range value generated by axes )

for axes, we should check the last values of axes are changed, if any value of axes changed since last time, the topic should be sent.

in current implementation, the axes are actually acted as a button like request in issue #79