Add convenience method to check if websockets required (#779)

* Add convenience method to check if websockets required

* Add tests

* Fix up tests for develop branch

context.go

@@ -383,6 +383,16 @@ func (c *Context) ContentType() string {
 	return filterFlags(c.requestHeader("Content-Type"))
 }
 
+// IsWebsocket returns true if the request headers indicate that a websocket
+// handshake is being initiated by the client.
+func (c *Context) IsWebsocket() bool {
+	if strings.Contains(strings.ToLower(c.requestHeader("Connection")), "upgrade") &&
+		strings.ToLower(c.requestHeader("Upgrade")) == "websocket" {
+		return true
+	}
+	return false
+}
+
 func (c *Context) requestHeader(key string) string {
 	if values, _ := c.Request.Header[key]; len(values) > 0 {
 		return values[0]