Allow URL's for codegen

[tacman1123]

I'd like to propose allowing URL's for the codegen_settings, instead of requiring a local, flat file. I'd like to integrate relationships based on some dynamic criteria, and want to make this happen in one step (that is, not create the file and then read it back in).

Here's the old code, in QCodeGenBase.php:

			if (!file_exists($strSettingsXmlFilePath)) {
				QCodeGen::$RootErrors = 'FATAL ERROR: CodeGen Settings XML File (' . $strSettingsXmlFilePath . ') was not found.';
				return;
			}

			if (!is_file($strSettingsXmlFilePath)) {
				QCodeGen::$RootErrors = 'FATAL ERROR: CodeGen Settings XML File (' . $strSettingsXmlFilePath . ') was not found.';
				return;
			}

I've just commented these lines out in my installation, and it fails if the url isn't valid, or the file isn't there. It's hard to test if a url is valid without opening the file, but I think failing as it does it okay.

Thoughts?