Update

devel/netsurf-buildsystem to 1.6
devel/nsgenbind to 0.5
dns/libnspsl to 0.1.2
graphics/libnsgif to 0.2.0
textproc/libcss to 0.7.0
textproc/libutf8proc to 1.3.1.3
www/libdom to 0.3.2
www/libhubbub to 0.3.4
www/netsurf to 3.7