Disable networking at runtime with lkmc_nonet cli instead of build

This is necessary because qemu and gem5 now use the same build folder.

Separate ./run -e and -f for kernel options before and after the ' - '.
This was already the better thing to do when -E was introduced,
but lkmc_nonet prompted me to do it nicer now.

Use the common script to find the out_dir on every toplevel script.

Include usage man pages on README.

count-boot-instructions

@@ -1,7 +1,17 @@
 #!/usr/bin/env bash
-set -e
-time ./run -n -e 'init=/poweroff.out' -- -trace exec_tb,file=trace
-time ./qemu/scripts/simpletrace.py buildroot/output.x86_64~/build/host-qemu-custom/trace-events-all trace >trace.txt
+set -eu
+. common
+arch=x86_64
+while getopts a: OPT; do
+  case "$OPT" in
+    a)
+      arch="$OPTARG"
+      ;;
+  esac
+done
+set_common_vars "$arch" false
+time ./run -a "$arch" -n -e 'init=/poweroff.out' -- -trace exec_tb,file=trace
+time ./qemu/scripts/simpletrace.py "${out_dir}/build/host-qemu-custom/trace-events-all" trace >trace.txt
 wc -l trace.txt
 sed '/0x1000000/q' trace.txt >trace-boot.txt
 wc -l trace-boot.txt