Support VPN over any native tethering

First big refactoring of this app.

mobile/src/main/java/be/mygod/vpnhotspot/SettingsPreferenceFragment.kt

@@ -0,0 +1,38 @@
+package be.mygod.vpnhotspot
+
+import android.content.Intent
+import android.net.Uri
+import android.os.Bundle
+import android.support.customtabs.CustomTabsIntent
+import android.support.v4.content.ContextCompat
+import com.takisoft.fix.support.v7.preference.PreferenceFragmentCompatDividers
+
+class SettingsPreferenceFragment : PreferenceFragmentCompatDividers() {
+    private val customTabsIntent by lazy {
+        CustomTabsIntent.Builder().setToolbarColor(ContextCompat.getColor(activity!!, R.color.colorPrimary)).build()
+    }
+
+    override fun onCreatePreferencesFix(savedInstanceState: Bundle?, rootKey: String?) {
+        addPreferencesFromResource(R.xml.pref_settings)
+        findPreference("service.clean").setOnPreferenceClickListener {
+            Routing.clean()
+            true
+        }
+        findPreference("misc.logcat").setOnPreferenceClickListener {
+            val intent = Intent(Intent.ACTION_SEND)
+                    .setType("text/plain")
+                    .putExtra(Intent.EXTRA_TEXT, Runtime.getRuntime().exec(arrayOf("logcat", "-d"))
+                            .inputStream.bufferedReader().use { it.readText() })
+            startActivity(Intent.createChooser(intent, getString(R.string.abc_shareactionprovider_share_with)))
+            true
+        }
+        findPreference("misc.source").setOnPreferenceClickListener {
+            customTabsIntent.launchUrl(activity, Uri.parse("https://github.com/Mygod/VPNHotspot"))
+            true
+        }
+        findPreference("misc.donate").setOnPreferenceClickListener {
+            customTabsIntent.launchUrl(activity, Uri.parse("https://mygod.be/donate/"))
+            true
+        }
+    }
+}