fetch2/wget: Check downloaded file isn't zero size

I can't think of a reason we'd download zero sized files however there are
reasons zero length files can accidently make it onto source mirrors.

This check allows us to ignore the broken files and switch to another
mirror rather than fail with odd checksum failures.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
runqueue: Only attempt to print closest matching task if there is a match

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
world-image: add extra target

* similar to world target, but collects all PACKAGES
* recipes marked with EXCLUDE_FROM_WORLD are excluded from world as well
  as world-image
* recipes marked with EXCLUDE_FROM_WORLD_IMAGE are excluded completely
  from world-image, sometimes you can build 2 recipes in same sysroot,
  but cannot install them in the same image
* PACKAGES listed in EXCLUDE_PACKAGES_FROM_WORLD_IMAGE are also
  excluded. You can remove e.g. ${PN}-dbg, but keep all other PACKAGES.

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>