scripts/image: no more .tar.bz. images coming soon
Makefile: add optional "make image" support
scripts/checkdeps: check for parted
bcm2835-bootloader/release: add initial "make image" support

BIG FAT WARNING:
this requires sudo at build-time. may not work with
auto-builds. check your etc/sudoers

BIG FAT WARNING:
this is a work in progress. use only if you know what you are doing.