Fetch fixes

july update:

What this does:
 - Adds support for all architectures but MIPS
 - security enhancements
 - quoting
 - code cleanup

What this doesen't do:
 - automatic setup of Qemu emulation for non-native containers


regarding quoting:
please quote *everything* in Bash (or any other shell) and force contributors to do this as well
If you want to see why, run create with -n "name with spaces" and enjoy the cleanup you'll have
to do after the script changes/adds "random" files on your host system.

regarding code cleanups:
I found two things in code that were unconnected with anything/unimplemented and traced the cause back
to you and @gza. It appears to me that they were a result of squashing all things into a single
commit or carelessness or both.

regarding things left to do:
 - automatic Qemu support: I'm not yet sure how deep I want to go with this. I guess copying
   qemu-$ARCH into the rootfs would make sense, but what if the user wanted to have a
   seperate repo for static binaries?. While installing qemu and configuring binfmt_misc
   are distro-specific things and I'd rather not have to code support for everything out there.
 - $ARCHVARIANT: this variable doesen't have a command-line argument yet. I evaluated various
   options that came to mind and decided neither is good enough to just commit and forget about
   it: -v is usually for verbosity, -V doesen't match up with -a and encoding it in -a
   "arm:armv7a-hardfp" would break compatibility with thatever people use to run this script
   with.
 - wget caching: wget should be wrapped up in a function that would cache things for as long
   the user wishes and not redownload a stage3 every week to keep up with autobuilds.
   (currently, the portage snapshot is not updated at all)
 - $CACHE/: I think the current layout under $CACHE is stupid and too deep.
   I recommend $CACHE/$ARCH-$ARCHVARIANT/...tar.* or $CACHE/$ARCH/$ARCHVARIANT/stage3-....tar.*
   and have the above caching keep one or two (or how many the user wishes) versions around.