Band names in .bnd files (issue #136)

BANDS->SD stored start, end and level only, so the band names were lost.
The name is now written as a quoted fourth field (older firmware ignores
it) and loaded when present (files of older firmware keep the current
names). A line needs start, end and level: the level was read from lines
with only two fields as well.

Tested on a ZS407: band named FMRADIO stored as
  0, 900000000, 0.000000000, "FMRADIO"
renamed, loaded from SD: FMRADIO again. tinySA Ultra only.

ui.c

@@ -8449,8 +8449,7 @@ static void sa_save_file(uint8_t format) {
             char *buf = (char *)spi_buffer;
             buf += plot_printf(buf, 100, "%U, ", setting.bands[i].start);
             buf += plot_printf(buf, 100, "%U, ", setting.bands[i].end);
-            buf += plot_printf(buf, 100, "%f ", setting.bands[i].level);
-            buf += plot_printf(buf, 100, "\r\n");
+            buf += plot_printf(buf, 100, "%f, \"%s\"\r\n", setting.bands[i].level, setting.bands[i].name);  // name: older firmware ignores it
             res = f_write(fs_file, (char *)spi_buffer, buf - (char *)spi_buffer, &size);
           }
         }

vna_browser.c

@@ -177,11 +177,13 @@ finish2:
           line[j] = 0; j = 0;
           char *args[16];
           int nargs = parse_line(line, args, 16);                            // Parse line to 16 args
-          if (nargs < 2 || args[0][0] == '#' || args[0][0] == '!') continue; // No data or comment or settings
+          if (nargs < 3 || args[0][0] == '#' || args[0][0] == '!') continue; // No data or comment or settings
           if (count >= BANDS_MAX) {error = "Format err"; goto finish3;}
           setting.bands[count].start = my_atoui(args[0]);// Get frequency
           setting.bands[count].end = my_atoui(args[1]);// Get frequency
           setting.bands[count].level = my_atof(args[2]);     // Get frequency
+          if (nargs > 3)                                     // Name, files of older firmware have none
+            plot_printf(setting.bands[count].name, BAND_NAME_SIZE, "%s", args[3]);
           setting.bands[count].enabled = true;               // Get frequency
           count++;
         }