lkmc v2-rc

Unsquashed version at v2-rc-unsquashed, but that cannot be merged as it
breaks bisects at several points. All bugs will not bisect to this
humongous change.

It all started with a conversion of the Bash scripts to Python, mainly
because I couldn't stand not being able to properly use --options for
run which has a million options.

Then since that required a full testing, I decided to do all the
refactorings that I had in mind at once, and so I did and it became
v2-rc.

This is the largest patch I have ever done! OMG a few weeks of extra time.
I'm never writing a Bash script for anything that starts getting big again.

Some of the features are:

* separate build-qemu and build-gem5 commands
* common: convert scripts to python. Add --option for everything
* rename build to build-buildroot now that we are splitting all the build
  commands, Linux kernel to follow
* move all git submodules to submodules/ and all buildroot packages to
  packages/
* refactor the out/ structure. Keep projects on toplevel, because guest
  projects separate archs and host ones don't, making a toplevel arch wrong
* do-release: rename to just release
  https://stackoverflow.com/questions/16174992/cant-get-argparse-to-read-quoted-string-with-dashes-in-it
* run: add --terminal and explain gem5 pdb
* just track the lvimrc
* store CLI kernel config fragment inside buildlroot to avoid conflicts
* gem5: document m5 initparam
* readme: make a bunch of things awesomer
* readme: fix broken refs
* parsec-benchmark: update to 75d55ac446a43c47efb1044844a108c6c330184c
  Could not fetch otherwise.
* gem5: M5_OVERRIDE_PY_SOURCE

build-all

@@ -1,18 +1,22 @@
 #!/usr/bin/env bash
 set -eu
 archs='x86_64 arm aarch64'
-gem5=-g
+gem5=true
 while getopts A:G OPT; do
   case "$OPT" in
     A)
       archs="$OPTARG"
       ;;
     G)
-      gem5=
+      gem5=false
       ;;
   esac
 done
 shift "$(($OPTIND - 1))"
 for arch in $archs; do
-  ./build -a "$arch" -klq $gem5 "$@"
+  ./build-qemu --arch "$arch"
+  ./build --arch "$arch" --kernel-modules -l "$@"
+  if "$gem5"; then
+    ./build-gem5 --arch "$arch"
+  fi
 done