gui miccanvas: don't fail setting HFW if heigh is null

It can happen in some cases, just do the same as was done for width:
don't do anything if one of the dimensions is 0 (anyway, the view is probably hidden)
config: fake sparc also needs pole_pos info

add some fake pole_pos
config: new simulator for SPARC with AR only

useful to test from time to time.
util img: make sure that bytescale and fast version give the same result

Change the way the rouding works, to make sure the fast version behaves the same
as bytescale.

By itself, the rouding way doesn't matter so much, but it's nice to know
the results are identical.
acq stream: add test for 1d spectrum parallel to an axis

Turns out that it already worked... but found other bugs.
Merge branch 'master' of vpn.delmic.com:odemis