web app band selection fix, and 60m added.

[laluha]

This pull request should fix issue #102
(I am new to "pull requests" but I hope this is usable. My llhdev branch is based on afarhandev)
Quoted from issue #102:

1. The buff argument to set_field in sbitx_gtx.c line 4252 needs to be set:

	sprintf(buff, "%d", new_band*10+stack);
	set_field("#selband", buff);

The value is two digits the first indicates the band and the last the current stack;

2. Due to the added 60M band the #selband "command" must have it max value increased.
   sbitx_gtx.c line 620 (new max value 83: band select 0-8 stack 0-3)

  { "#selband", NULL, 1000, -1000, 50, 50, "SELBAND", 40, "", FIELD_NUMBER, FONT_FIELD_VALUE,
    "", 0,83,1, 0},

3. The 60M band needs to be added in index.html line 78

<button class="sbitxv3-btn" id="60M" type="submit">60M<span id="S60" class="selband"></span></button>

4. I had to add the 60M band to the hw_settings.ini. Something like

[tx_band]
f_start=5250000
f_stop=5450000
scale=0.0156247

After this I was able to make my first ft8 contact on 60M using the web app :-)