Remove warnings

These changes remove lots of calls to deprecated methods, most notably:

· HTTPRequest.getPartAsString
· PageMaker.getPageNode in various forms
· PageMaker.parseMode(HTTPRequest, ToadletContainer)
· NodeClientCore.makeClient

It also suppresses a lot of warnings about using deprecated methods (e.g. db4o’s query.execute()) and unchecked casts.

As a result, “ant clean dist” on my machine does currently does not print a single warning when using Java 6. (Java 7 still has some, I’ll tackle those next.)