Restrict model class name charset

[Lythimus]

Using HL7 XSD schema https://dl.dropboxusercontent.com/u/8709992/HL7.xsd, I found that elements with periods in their name attributes were converted into classes with periods in their names, which is illegal syntax based on the PHP standard. I recommend name attributes be processed and substituted with legal characters as this is probably a general issue, not restricted to periods.

I do not receive an error or warning when generating the PHP classes from the XSD file. Rather PHP throws an error when trying to load the files.

This library seems good, but unfortunately due to lack of documentation and minor hangups, I'm going to parse my XML files manually. Not to dissuade you from working on the tool. But I've found most people have a low threshold for incorporating these sorts of libraries and will quickly fall back to one-off hacks due to time constraints.