New feature : access to spring application context from groovy interceptor

example :
    <spring:bean name="mySpringBean" class="java.lang.String">
        <spring:constructor-arg value="Groovy interceptor"/>
    </spring:bean>

    <router>
        <serviceProxy port="2000">
            <request>
                <groovy>
                    def value = spring.getBean("mySpringBean")
                    exc.request.header.add("X-Groovy", value)
                    println "X-Groovy header added with value :" + value
                    CONTINUE
                </groovy>
            </request>
        </serviceProxy>
    </router>