update tests again
update cimg, integrate gmic

try:

$ vips gmic 1 x.jpg 20 1 1 --in0 k2.jpg -- "-blur 10"

output is black, but it does seem to almost work
gmic uses an imagevec for input images
process all gmic images as float
small tidies to vips_gmic.cpp
support uchar and ushort gmic images
add --with-gmic configure option
fix extra band handling in colour

backport of new colour.c from 7.41
Merge branch '7.40'

Conflicts:
	ChangeLog
	configure.ac
	libvips/colour/Lab2LabQ.c
	libvips/colour/Lab2LabS.c
	libvips/colour/LabS2Lab.c
	libvips/colour/LabS2LabQ.c
	libvips/colour/float2rad.c
	libvips/colour/sRGB2scRGB.c
	libvips/colour/scRGB2sRGB.c
improve interpretation of maplut output

a mono image though a colour lut needs to take the lut's interpretation
Merge remote-tracking branch 'origin/7.40'

Conflicts:
	ChangeLog
remove cimg and gmic

move this to a plugin, it's too big for the core library
Merge remote-tracking branch 'origin/master' into update-cimg
add vips8 plugin support
allow tiffs with >1000 pages

all sanity checks run out eventually :(
update potfiles