WIP: fix the manual color integration.

The problem is that you really need to flag feature analyzers that deal
with manual features. Because they are reset just before saving. And you
loose the values you set manually.
This might be the time for a redesign.
This might then be the moment to devlare int features...
Signed-off-by: Jean-Yves Tinevez <jeanyves.tinevez@gmail.com>