Integration test for FacesExpressionLanguageProvider

Hey Lincoln,

I added the integration test for the new `FacesExpressionLanguageProvider` we talked about. Works fine.

However I'm also seeing a strange exception here in the logs although the test works fine:

```
INFO: RewriteFilter initialized.
10.04.2012 07:25:39 org.eclipse.jetty.util.log.Slf4jLog info
INFO: WebApp@1589782904 at http://localhost:9090/rewrite-test
log4j:WARN No appenders could be found for logger (org.apache.http.impl.conn.SingleClientConnManager).
log4j:WARN Please initialize the log4j system properly.
10.04.2012 07:25:40 org.eclipse.jetty.util.log.Slf4jLog warn
WARNUNG: Committed before 404 null
10.04.2012 07:25:40 org.eclipse.jetty.util.log.Slf4jLog warn
WARNUNG: /rewrite-test/name/christian
java.lang.IllegalStateException: Committed
	at org.eclipse.jetty.server.Response.resetBuffer(Response.java:1066)
	at org.eclipse.jetty.server.Response.sendError(Response.java:274)
	at org.eclipse.jetty.server.Response.sendError(Response.java:376)
	at javax.servlet.http.HttpServletResponseWrapper.sendError(HttpServletResponseWrapper.java:162)
	at org.eclipse.jetty.servlet.DefaultServlet.doGet(DefaultServlet.java:472)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:734)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:550)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1359)
	at org.ocpsoft.rewrite.servlet.RewriteFilter.doFilter(RewriteFilter.java:183)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1330)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:484)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:517)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:233)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:970)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:414)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:192)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:904)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:149)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:110)
	at org.eclipse.jetty.server.Server.handle(Server.java:347)
	at org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:439)
	at org.eclipse.jetty.server.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:907)
	at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:562)
	at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:214)
	at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:43)
	at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:545)
	at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:43)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:529)
	at java.lang.Thread.run(Thread.java:679)
10.04.2012 07:25:40 org.ocpsoft.logging.slf4j.SLF4JLogAdapter log
INFO: RewriteFilter shutting down...
```

Any idea?