Implemented more commands from REST API JSONWireProtocol

Refactor COMMAND_EXECUTOR.

library/test/selenium/src/helpers/http_methods.e

@@ -0,0 +1,19 @@
+note
+	description: "Summary description for {HTTP_METHODS}."
+	author: ""
+	date: "$Date$"
+	revision: "$Revision$"
+
+class
+	HTTP_METHODS
+
+feature -- Method Names
+	OPTIONS : STRING_32 = "OPTIONS"
+	GET : STRING_32 = "GET"
+	HEAD : STRING_32 = "HEAD"
+	POST : STRING_32 = "POST"
+	PUT	 : STRING_32 = "PUT"
+	DELETE : STRING_32 = "DELETE"
+	TRACE  : STRING_32 = "TRACE"
+	CONNECT : STRING_32 = "CONNECT"
+end