Leica LIF: do not set the 'rgb' flag for 16-bit multi-channel data

Multi-channel images with more than 8 bits per pixel are not stored as
RGB images, even though the stored byte count suggests that they might
be.

See QA 7695 and
http://lists.openmicroscopy.org.uk/pipermail/ome-users/2013-November/004051.html
Revert "Leica LIF: do not set the 'rgb' flag for 16-bit multi-channel data"

This reverts commit a5eaffdf20b0e89cc7eca65e95b2b2d20df0b09b.
ImageTools: fix BGR-to-RGB conversion for >8 bit data

See QA 7695 and
http://lists.openmicroscopy.org.uk/pipermail/ome-users/2013-November/004051.htm
Merge pull request #783 from melissalinkert/rgb-leica-lif

Leica LIF: do not set the 'rgb' flag for 16-bit multi-channel data