feat: Honor radio's option to use Fahrenheit (#658)

app/src/main/java/com/geeksville/mesh/NodeInfo.kt

@@ -174,8 +174,9 @@ data class NodeInfo(
     private fun envFormat(f: String, unit: String, env: Float?): String =
         if (env != null && env != 0f) String.format(f + unit, env) else ""
 
-    val envMetricStr
-        get() = envFormat("%.1f", "°C ", environmentMetrics?.temperature) +
+    fun envMetricStr(isFahrenheit: Boolean = false): String =
+        if (!isFahrenheit) envFormat("%.1f", "°C ", environmentMetrics?.temperature)
+        else envFormat("%.1f", "°F ", environmentMetrics?.temperature?.times(1.8f)?.plus(32)) +
                 envFormat("%.0f", "%% ", environmentMetrics?.relativeHumidity) +
                 envFormat("%.1f", "hPa ", environmentMetrics?.barometricPressure) +
                 envFormat("%.0f", "mΩ ", environmentMetrics?.gasResistance) +

app/src/main/java/com/geeksville/mesh/ui/UsersFragment.kt

@@ -205,8 +205,9 @@ class UsersFragment : ScreenFragment("Users"), Logging {
 
             holder.lastTime.text = formatAgo(n.lastHeard)
 
-            if (n.envMetricStr.isNotEmpty()) {
-                holder.envMetrics.text = n.envMetricStr
+            val envMetrics = n.envMetricStr(model.module.telemetry.environmentDisplayFahrenheit)
+            if (envMetrics.isNotEmpty()) {
+                holder.envMetrics.text = envMetrics
                 holder.envMetrics.visibility = View.VISIBLE
             } else {
                 holder.envMetrics.visibility = View.GONE