start-debian.sh: always use the best available filesystem (ext2/3/4)

It seems that a filesystem that has been formatted as ext2 will mount fine
as ext4, so always use the best available filesystem.
convert all shebangs to use the busybox sh included in the app's app_bin/
simplify PATH in scripts to use included tools first, then default PATH

Before the busybox suite was included, the app needed to make sure that it
found all the included utils. Now it comes with everything it needs builtin
make writeCommand() log command to logcat
sometimes the ssh host keys aren't created on setup, so try again manually
set app version to v0.4.1 build 6
add script for the release build process