Refactor and update RocketChat bridge

* Add support for editing/deleting messages
* Add support for uploading files
* Add support for avatars
* Use the Rocket.Chat.Go.SDK
* Use the rest and streaming api

vendor/github.com/matterbridge/Rocket.Chat.Go.SDK/realtime/subscriptions.go

@@ -0,0 +1,41 @@
+package realtime
+
+import (
+	"fmt"
+
+	"github.com/gopackage/ddp"
+)
+
+// Subscribes to stream-notify-logged
+// Returns a buffered channel
+//
+// https://rocket.chat/docs/developer-guides/realtime-api/subscriptions/stream-room-messages/
+func (c *Client) Sub(name string, args ...interface{}) (chan string, error) {
+
+	if args == nil {
+		//log.Println("no args passed")
+		if err := c.ddp.Sub(name); err != nil {
+			return nil, err
+		}
+	} else {
+		if err := c.ddp.Sub(name, args[0], false); err != nil {
+			return nil, err
+		}
+	}
+
+	msgChannel := make(chan string, default_buffer_size)
+	c.ddp.CollectionByName("stream-room-messages").AddUpdateListener(genericExtractor{msgChannel, "update"})
+
+	return msgChannel, nil
+}
+
+type genericExtractor struct {
+	messageChannel chan string
+	operation      string
+}
+
+func (u genericExtractor) CollectionUpdate(collection, operation, id string, doc ddp.Update) {
+	if operation == u.operation {
+		u.messageChannel <- fmt.Sprintf("%s -> update", collection)
+	}
+}