IR and XPath DM implementation

Hi,

Just a quick note to say that hscxml [1] now implements the XPath data
model, to the extent that it passes all required XPath specific tests.
While hscxml cross-compiles to a variety of targets (Neko, C++, JS, and
Flash ..with others likely to follow), the XPath data model is Flash
specific, due to the library in use. This may change in future, but the
main goal of this implementation is to help the SCXML specification
progress to Recommendation phase asap.

The primary compilation target for the non-XPath specific tests is Neko.
All these tests pass for both the ECMAScript and hscript data models.
Please find the hscxml IR here [2].

Finally, it would be wonderful to retain the work related to the DOM Event
I/O Processor, not only as an acknowledgement of efforts over the years,
but also because defining basic integration points seems quite fitting for
an accessible technology.

The DOM Event I/O Processor is supported in hscxml and there are 1 or 2
basic tests for it already [3]. If anyone else is willing to help push that
forward, please let us know.

br,
Zjnue

[1] https://github.com/zjnue/hscxml
[2]
https://github.com/zjnue/hscxml/blob/master/test/files/report/scxml10-ir-results-template.xml
[3] https://github.com/zjnue/hscxml/blob/master/test/js/testdom001.scxml
https://github.com/zjnue/hscxml/blob/master/test/js/testdom002.scxml