package.bbclass: Split into two tasks, one which prepares the packages and then packa...

package.bbclass: Split into two tasks, one which prepares the packages and then package_write which actually generates the packages. The two stage approach allows us to avoid circular dependency issues from classes like debian.bbclass. As the data being emitted into pkgdata/ changed, you need to either wipe tmp or rerun the do_install/do_package tasks (wipe the do_xyz stamps from the stamps dir). Everything will repackage anyway due to the new task.

git-svn-id: https://svn.o-hand.com/repos/poky/trunk@807 311d38ba-8fff-0310-9ca6-ca027cbcb966