Add backup entry for custom rules

Refine #1069.

src/main/scala/com/github/shadowsocks/ShadowsocksBackupAgent.scala

@@ -21,6 +21,7 @@
 package com.github.shadowsocks
 
 import android.app.backup.{BackupAgentHelper, FileBackupHelper, SharedPreferencesBackupHelper}
+import com.github.shadowsocks.acl.Acl
 import com.github.shadowsocks.database.DBHelper
 
 class ShadowsocksBackupAgent extends BackupAgentHelper {
@@ -38,6 +39,7 @@ class ShadowsocksBackupAgent extends BackupAgentHelper {
   override def onCreate() {
     val helper = new SharedPreferencesBackupHelper(this, PREFS_DISPLAY)
     addHelper(MY_PREFS_BACKUP_KEY, helper)
-    addHelper(DATABASE, new FileBackupHelper(this, "../databases/" + DBHelper.PROFILE))
+    addHelper(DATABASE, new FileBackupHelper(this, "../databases/" + DBHelper.PROFILE,
+      "../" + Acl.CUSTOM_RULES + ".acl"))
   }
 }

src/main/scala/com/github/shadowsocks/acl/Acl.scala

@@ -51,15 +51,15 @@ class Acl {
     bypass = other.bypass
     this
   }
-  def fromSource(value: Source): Acl = {
+  def fromSource(value: Source, defaultBypass: Boolean = false): Acl = {
     bypassHostnames.clear()
     proxyHostnames.clear()
     this.subnets.clear()
-    bypass = false
+    bypass = defaultBypass
     lazy val bypassSubnets = new mutable.SortedList[Subnet]()
     lazy val proxySubnets = new mutable.SortedList[Subnet]()
-    var hostnames: mutable.SortedList[String] = bypassHostnames
-    var subnets: mutable.SortedList[Subnet] = bypassSubnets
+    var hostnames: mutable.SortedList[String] = if (defaultBypass) proxyHostnames else bypassHostnames
+    var subnets: mutable.SortedList[Subnet] = if (defaultBypass) proxySubnets else bypassSubnets
     for (line <- value.getLines()) (line.indexOf('#') match {
       case -1 => line
       case index => line.substring(0, index)  // trim comments