Make the loading icon optional

[Samuel Alba]

Hi TouchTerm group,

First of all I would like to congrats the developer(s?) of this
wonderful app.

IMHO, the display of the loading icon should be optional and should be
toggled in the prefs menu. I use gnu screen on my server (through
byobu) so updates are sent continously to the client. So I always see
the loadind icon on my screen. However i think loading icon is useful
on a normal ssh connection to see what happens.

What do you think?

Best,

Sam