Add placeholder files for empty directories

These should be cleaned out prior to building a kernel,
but they need to be here so git tracks the directories.

Some people use .gitignores, but per LinuxBozo recommendations
I use EMPTY_DIRECTORY - it's a bit more obvious.

My kernel source repo will eventually include a build script that copies
initramfs and cleans these out
init.d support (Entropy512)
Implemented post-init script and MDNIE sharpness fix (gokhanmoral)