Implement MAC lookup (#68)

* Implement MAC lookup

* Refine error processing

* Use long to store MAC consistently

* Link back to macvendors.co

* Undo some havoc

* Do not show mac spans for TV

* Show MAC and IP in a consistent order

* Add IP spans by ipinfo.io

* Add SpanFormatter

* Fix IPv6 ipinfo.io link

* Refine SpanFormatter

* Fix pressing the link

mobile/src/main/java/be/mygod/vpnhotspot/room/Converters.kt

@@ -50,8 +50,9 @@ fun String.macToLong(): Long = ByteBuffer.allocate(8).run {
     long
 }
 
+fun Iterable<Byte>.macToString() = joinToString(":") { "%02x".format(it) }
 fun Long.macToString(): String = ByteBuffer.allocate(8).run {
     order(ByteOrder.LITTLE_ENDIAN)
     putLong(this@macToString)
-    array().take(6).joinToString(":") { "%02x".format(it) }
+    array().take(6).macToString()
 }