Fix python 2.6 compat issues with field numbering

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
bb-whatdepends,bbcmd: ignore ASSUME_PROVIDED targets

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
bb-init: use alias for zsh too

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
bb-init: prepend to PATH, don't append

Signed-off-by: Christopher Larson <chris_larson@mentor.com>