update doc.go

doc.go

@@ -1,16 +1,22 @@
 /*
 
-## Features:
+A Parser for PHP written in Go
+
+Features:
 
 	Fully support PHP5 and PHP7 syntax
 	Abstract syntax tree representation
 	Traversing AST
 
-## Install
+Install
 
 	go get github.com/z7zmey/php-parser
 
-Example
+CLI dumper
+
+	$GOPATH/bin/php-parser -php5 /path/to/file/or/dir
+
+Package usage example
 
 	package main