[Cornell] comment out Arxiv; will be its own rule when it works
[Svenskakyrkan] broken, disable
[Cloudfront] Amazon.com MP3 player exclusion

https://trac.torproject.org/projects/tor/ticket/9851
Bump version to 3.4.3
Disable ContentPolicy callbacks, if channel.redirecTo() is available.

Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=939180

This is implemented in 3.x by keeping the callbacks but not actually using
them.  For elegance and performance we should probably not register for them at
all, but I'm a little unsure about whether the version-comparator service might
take a while to appear during startup.

4.x has a better solution, which is to never register and simply be
incompatible with FF < 20.
Merge Changelog for 4.0development.14

Conflicts:
	src/Changelog