XML_PullParser implements Error tracing

XML_PullParser 1.2.0 is a major new release which adds error reporting and tracing to earlier versions. Errors are handled by a new class,
XML_PullParser_Errors. User defined errors are also supported; these are pushed onto XML_PullParser's error stack and become part of any trace, making it possible to track errors in user code back to problems which may have originated in the use of XML_PullParser itself.
Error reporting is explained in the Manual.

Of interest to current users: This release also contains a bug fix to XML_PullParser_setAttrLoop_elcd() and a new method, XML_PullParser_tokenFromChildren(), which creates tokens from arrays returned
by XML_PullParser_getChildren().

XML_PullParser 1.2.0 is backwardly compatible with earlier versions of XML_PullParser but now requires PHP version >= 4.3.