Remove for each...in code

"The for each...in statement is deprecated as the part of ECMA-357 (E4X) standard."
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for_each...in
Cleanup -moz-border-*-colors and -moz-border-radius
Cleanup arguments.callee
Remove about.xul

about.xul is no longer needed.
v0.0.3

* Update support for Tumblr Reblog
* Extractor: Drop support for "Photo - Picoolio.co.uk"
* Cleanup for each...in, -moz-border-*-colors, -moz-border-radius, arguments.callee
* Remove about.xul