remove outdated virtualbox ebuilds
add ebuild for Brother DCP7055W CUPS driver

based on
 - https://github.com/mrpdaemon/gentoo-overlay/tree/master/net-print/cupswrapper-brother-hl2270dw
 - https://github.com/mrpdaemon/gentoo-overlay/tree/master/net-print/lpdfilter-brother-hl2270dw
 - https://aur.archlinux.org/packages/brother-dcp7055w-cupswrapper/
 - https://aur.archlinux.org/packages/brother-dcp7055w-lpr/