[arm-allstar] removing squelch crash with the SA818

[Steve Smith]

I have modified the 818-prog program to include the capability to set 
reverse burst to off/on using the "AT+SETTAIL=TAIL" command . The 
modified program is called shari-pixx-prog.  It can be downloaded from 
www.groups.io/g/shari/files  Note that there is no checking done to 
check the command "AT+SETTAIL=TAIL" because it erroneously returns a '0' 
for either setting (0 or 1).

When using the program '0' means no CTCSS reverse burst and '1' means 
send CTCSS reverse burst.  If you want to experiment with reverse burst 
o an SA-818, you can upload the program to the /usr/local/sbin folder of 
your Pi using WinSCP. After you upload it be sure to make it executable 
by right clicking on it from within WinSCP and checking the three 
executable boxes (boxes labeled X). You run the program the same way you 
run 818-prog.

For this to work, the radio you are using to talk to your node must 
support reverse burst.

It turns out that the default setting for the SA818 used in SHARI is 
reverse burst turned on.  I use a Kenwood TH-F6A and hear no squelch 
tail with it turned on.

Steve - N8AR