Add missing javadocs.

src/main/scala/model/handler/Handler.scala

@@ -15,5 +15,8 @@ trait Handler {
 }
 
 trait HandlerCompanion {
+	/**
+	 * Http server context (path).
+	 */
 	val CONTEXT: String
 }

src/main/scala/model/lib/HttpUtil.scala

@@ -4,6 +4,11 @@ package model.lib
 import java.net.{MalformedURLException, URL}
 
 object HttpUtil {
+	/**
+	 * Check if string is a correct url.
+	 * @param url String to check.
+	 * @return True if url is valid.
+	 */
 	def isUrl(url: String): Boolean = {
 		try {
 			new URL(url)