adopt behavior of firefox

- read subscription.xml by zip.BlobWriter, as zip.TextWriter not works in firefox
- convert xml response to dom if needed
- add a xml selector
- modify note by a little
specify host with IP, in case it got banned
change path of <self as submodule>
downloadable chrome extension
add feedzombie as submodule
Merge remote-tracking branch 'origin/feedzombie' into source
minor update
update feedzombie to v0.2