- new interface:
   new pmxdr(host), a reusable pmxdr interface
- pmxdrInstance.onload
- pmxdrInstance.init
- pmxdrInstance.request
- pmxdrInstance.unload
- for old functionality, use pmxdr.request
- pmxdr.destruct() removes pmxdr and it's message listeners
- pmxdr.prototype.defaultRequestMethod is now default request method
- pmxdr.prototype.defaultX properties
- general code cleanup
- remove abstracted to abort