Add shutdown command to API

- calling "shutdown" now cleanly shuts down PyBitmessage, however the
call may not return so you need to add an error handler to the call.
With python for example, wrap the "shutdown()" in
"try:/except socket.error"

src/api.py

@@ -30,6 +30,7 @@ import protocol
 import state
 from pyelliptic.openssl import OpenSSL
 import queues
+import shutdown
 from struct import pack
 import network.stats
 
@@ -982,6 +983,10 @@ class MySimpleXMLRPCRequestHandler(SimpleXMLRPCRequestHandler):
         sqlStoredProcedure('deleteandvacuume')
         return 'done'
 
+    def HandleShutdown(self, params):
+        shutdown.doCleanShutdown()
+        return 'done'
+
     handlers = {}
     handlers['helloWorld'] = HandleHelloWorld
     handlers['add'] = HandleAdd
@@ -1032,6 +1037,7 @@ class MySimpleXMLRPCRequestHandler(SimpleXMLRPCRequestHandler):
     handlers['clientStatus'] = HandleClientStatus
     handlers['decodeAddress'] = HandleDecodeAddress
     handlers['deleteAndVacuum'] = HandleDeleteAndVacuum
+    handlers['shutdown'] = HandleShutdown
 
     def _handle_request(self, method, params):
         if (self.handlers.has_key(method)):