Add Slack support

vendor/github.com/nlopes/slack/emoji.go

@@ -0,0 +1,27 @@
+package slack
+
+import (
+	"errors"
+	"net/url"
+)
+
+type emojiResponseFull struct {
+	Emoji map[string]string `json:"emoji"`
+	SlackResponse
+}
+
+// GetEmoji retrieves all the emojis
+func (api *Client) GetEmoji() (map[string]string, error) {
+	values := url.Values{
+		"token": {api.config.token},
+	}
+	response := &emojiResponseFull{}
+	err := post("emoji.list", values, response, api.debug)
+	if err != nil {
+		return nil, err
+	}
+	if !response.Ok {
+		return nil, errors.New(response.Error)
+	}
+	return response.Emoji, nil
+}