bitbake: update as of 2013-04-12 17:10:11 +0000

56eac6e codeparser: Track bb.utils.contains usage
6568534 codeparser: Track appendVar and prependVar calls as we do for getVar

* These 2 commits are important fixes e.g. for using DISTRO_FEATURES
  more and more in contains functions.
* More info: https://bugzilla.yoctoproject.org/show_bug.cgi?id=3890
* Buildhistory verified no change in image.
* A lot of recipes will rebuild because of this.

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: I466895232e4311bf8ddcb439bb86468a74220f02