Add note to rebuild after change a br config

Not rebuilding buildroot after a change seems to be one of the top
issues. Hopefully this will help people.
Pull in support for fwupdate using external unzip

This significantly reduces firmware programming time. The key changes
are in the nerves-utils project.
rpi_qt5: add config supporting qt5 and webkit

This also bumps the rootfs max size to 128 MB like specified in
fwtool.config in the comments.
new package: blstrobe

This utility communicates with BenQ monitors via the DDC bus to control
backlight flicker timing.