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/util/CustomTabsUrlSpan.kt

@@ -0,0 +1,8 @@
+package be.mygod.vpnhotspot.util
+
+import android.text.style.URLSpan
+import android.view.View
+
+class CustomTabsUrlSpan(url: String) : URLSpan(url) {
+    override fun onClick(widget: View) = widget.context.launchUrl(url)
+}