Remove BUSYBOX variable from ramdisk-defaults

ramdisk-defaults file is sourced before chroot to an image being created
is executed. Busybox path should be set inside chroot instead.

Change-Id: Ic0e1d3093ca9d489dd96b14157e93b336cf0baee
Add *.egg to .gitignore

Change-Id: I398d07cf2c1e07554566711b4904ccbb46df2bcb
Merge "Add *.egg to .gitignore"
Allow heat-admin to sudo without tty

This is needed to run scripts from devtest, in particular so that
swift ring files can be distributed.

Change-Id: Icbe8c5b24a0d494730357983f230a37a7f078de7
Add mapping for libffi-dev

libffi header files are needed to pip install xattr, which is a
requirement of swift.

Change-Id: I69560425f7106c35ec432825eab94ca8424eb89e
Merge "Python code refactorings."
Merge "Allow heat-admin to sudo without tty"
Merge "Add mapping for libffi-dev"
Usage message enhancement

Add --help, add a simple usage and two examples

Change-Id: Iddf07ec1935f337000bd8ffb3d7c1fcc65753e8d
Merge "Usage message enhancement"
Add ability to apply elements to current system.

This commit adds the ability to apply diskimage-builder style elements
to the current system, as opposed to a chroot.  The functionality is
implemented in new python modules under diskimage_builder.  A script
using this python code at bin/element-runner is also included.  There
are some simple test elements under diskimage_builder/tests/elements to
aid with testing/verification as well.

Change-Id: Ic2bcb8b9f17e03709048ee4702270ede9a95d064