Option UNITS=IMPERIAL added

SD card archive function continued (doesn't delete the model until function finished)
Alternate view for outputs in Main Views (Bars and Numbers)
GPS speed was badly displayed (ap instead of bp)

src/frsky.cpp

@@ -851,6 +851,19 @@ int16_t convertTelemValue(uint8_t channel, uint8_t value)
 
 void putsTelemetryValue(uint8_t x, uint8_t y, int16_t val, uint8_t unit, uint8_t att)
 {
+#ifdef IMPERIAL_UNITS
+  if (unit == UNIT_DEGREES) {
+    val += 18 ;
+    val *= 115 ;
+    val >>= 6 ;
+  }
+  if (unit == UNIT_METERS) {
+    // m to ft *105/32
+    val = val * 3 + ( val >> 2 ) + (val >> 5) ;
+    unit = UNIT_MAX;
+  }
+#endif
+
   lcd_outdezAtt(x, (att & DBLSIZE ? y - FH : y), val, att & (~NO_UNIT)); // TODO we could add this test inside lcd_outdezAtt!
   if (~att & NO_UNIT && unit != UNIT_RAW)
     lcd_putsiAtt(lcd_lastPos/*+1*/, y, STR_VTELEMUNIT, unit, 0);
@@ -864,6 +877,7 @@ static const pm_uint8_t bchunit_ar[] PROGMEM = {
   UNIT_DEGREES, // T2
   UNIT_KMH,     // Speed
   UNIT_METERS,  // Dist
+  UNIT_METERS,  // GPS Alt
 };
 
 void putsTelemetryChannel(uint8_t x, uint8_t y, uint8_t channel, int16_t val, uint8_t att)