Better Fusion errors

So I'm currently hacking on Fusion to make it try and give us errors (if any occur) that actually mean something instead of a wall-of-gibberish that's alert()'ed out.

Now this is an error in Fusion that actually contains useful information!

And if you're wondering how useful that above error was, it told me that the CreateSession.php helper script had some syntactical compatibility issues for PHP 5.5, something that obviously slipped under the radar when I was upgrading PHP and assorted PHP code for the next release of MapGuide Open Source.

So in the process of building this feature, it immediately went straight to work and caught some server-side problem that would've taken several debug cycles to dig out. And I didn't even have to break into Firebug/Developer Tools to get this information! I'm loving the taste of this dogfood already!