Added `FileHandler` to handle files and images.
Merge branch 'master' of github.com:dkuntz2/java-httpserver

Conflicts:
	httpserver/HTTPHandler.java
	javadoc/allclasses-frame.html
	javadoc/allclasses-noframe.html
	javadoc/constant-values.html
	javadoc/demo/DemoDriver.html
	javadoc/demo/DemoHTTPHandlerFactory.html
	javadoc/demo/HelloHandler.html
	javadoc/demo/MathHandler.html
	javadoc/demo/package-frame.html
	javadoc/demo/package-summary.html
	javadoc/demo/package-tree.html
	javadoc/deprecated-list.html
	javadoc/help-doc.html
	javadoc/httpserver/HTTPException.html
	javadoc/httpserver/HTTPHandler.html
	javadoc/httpserver/HTTPHandlerFactory.html
	javadoc/httpserver/HTTPRequest.html
	javadoc/httpserver/HTTPResponse.html
	javadoc/httpserver/HTTPServer.html
	javadoc/httpserver/package-frame.html
	javadoc/httpserver/package-summary.html
	javadoc/httpserver/package-tree.html
	javadoc/index-all.html
	javadoc/index.html
	javadoc/overview-frame.html
	javadoc/overview-summary.html
	javadoc/overview-tree.html
	javadoc/package-list
	javadoc/serialized-form.html