New stuff

Fix all ebuild`s headers.
Add layman`s overlay.xml. Add layman to README.
Bump (Sync with gentoo) app-portage/gentoolkit-0.3.0.7-r1 -> app-portage/gentoolkit-0.3.0.7-r3
Bump (Sync with gentoo) sys-devel/gcc-config-1.7.3-r1 -> sys-devel/gcc-config-1.8-r1