lib/devel/kernel_compilation: support @defconfig

+ kcomp_reinit(): do not fail if $initial_config is empty
initramfs: load liram layouts from files

+ optionally download layout files via http/rsync (or from sysdisk)

This allows to play around with layouts without having to put them in
the initramfs.
lib/devel/kernel_compilation: fix uImage creation

The old way of way of appending the device tree to KERNEL_TARGET (usually
zImage) and the calling "make uImage" does no longer work (as of 3.14.x,
known to work with 3.10.x).

This commit replaces the "make uImage" step with a "mkimage".
fs/mount/domount, domount2(): fix argv handling
lib/fs: add zram module

Basic support for creating zram-backed filesystems / swap devices.
zram/fs: cleanup, + autoswap
initramfs: add support for zram_swap setup
zram: fix #1
zram: fix #2
zram: fix #3
zram: fix #4
zram: fix #5
zram: add logger shortcut functions
initramfs/zram: include zram disk support
zram, mkfs: typo
fs/zram: cleanup, comments & dotmpfs()
initramfs: include fs/zram/tmpfs
zram: typo
fix zram_tmpfs_parse_opts_unpacked()
initramfs/cmdline/parse: don't log unknown args

call argparse_unknown() in debug mode only