Crash recovery for NAT mode

Bugfix: when NAT process is killed, Internet access is gone. Reproduce with:

    adb shell killall com.github.shadowsocks:nat

One circumstance it cannot recover from is when updating to a new version, where both processes are killed at the same time. But a reset will be executed when the new version is launched.

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

@@ -275,7 +275,7 @@ class Shadowsocks
     }
   }
 
-  private def crashRecovery() {
+  def crashRecovery() {
     val cmd = new ArrayBuffer[String]()
 
     for (task <- Array("ss-local", "ss-tunnel", "pdnsd", "redsocks", "tun2socks")) {
@@ -477,7 +477,9 @@ class Shadowsocks
     handler.removeCallbacksAndMessages(null)
   }
 
-  def install() {
+  def reset() {
+    crashRecovery()
+
     copyAssets(System.getABI)
 
     val ab = new ArrayBuffer[String]
@@ -487,12 +489,6 @@ class Shadowsocks
     Console.runCommand(ab.toArray)
   }
 
-  def reset() {
-    crashRecovery()
-
-    install()
-  }
-
   def recovery() {
     serviceStop()
     val h = showProgress(R.string.recovering)

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

@@ -16,6 +16,7 @@ class ShadowsocksDeathRecipient(val mContext: ServiceBoundContext)
     mContext match {
       case ss: Shadowsocks =>
         ss.deattachService
+        ss.crashRecovery
         ss.attachService
       case _ =>
     }