Add deadzone test

Systick trigger working.
New deadzone block.

using:   $ ./configure --host arm-none-eabihf --disable-vesp --disable-am335x --disable-ethercat CFLAGS=-specs /usr/local/arm-none-eabihf/lib/atsamx70x21_flash.specs
(add quotes to spec argument)

luckily we never needed it.

Currently only supports ex2, but more can be added similar to andN.

Modified dt.ctrl to use the ex2 block to prevent simultanious activation of
focusbox outputs.

Made and block calculate functions status to prevent conflicts.

Make a few servers conditional on ctrl file
Improve some socket logging.

- Correctly display safety status
- Add override status

Small pwm fix
(added t_off)
vesp fixes, communication seems to be buggy

Add 't_off' parameter to am335 pwm block.
t_off will be the minimum time the bridge is switched low per pwm period.
(To allow boost C to recharge)

Can be used to quickly send float setpoints for testing.

(This might cause order dependent bugs...)

Fix vesp controller block.

Can be used to calculate a voltage limit based on the current voltage and
current and a current limit.

Add script to enable pwm on beaglebone

Determines current limit based on the i2t algorithm.

With this block motor state can be derived from voltage and speed.

Tested with beckhoff blocks connected.
(Still only one ethercat bus, multiple busses remains untested.)