Add umask task control

Add umask task control

Bitbake now allows the umask to be specified per task.  The
following tasks will have a umask of 022 set by default:

do_configure
do_compile
do_install
do_package
do_populate_sysroot
do_rootfs

do_configure and do_compile need a umask of 022 set because -many- recipes
directly copy generated files out of recipe's build directory.  Instead of
fixing each existing and future recipe, it was shown to be much easier to
just set the umask.

Signed-off-by: Mark Hatle <mark.hatle@windriver.com>