D::Light plugin improvements

[FloEdelmann]

As @sl1200mk2 told me via email, there are 3 improvements for the D::Light plugin to make:

Use EXTRA instead of INTENSITY

I've an issue with Briteq _ Pro Beamer Zoom Indoor (Tour 8 bit).
offset n°8 is classed as INTENSITY attribute (as offset 1) but D::Light only understand 1 offset as INTENSITY (for several reasons...)
would it be possible to set offset8 as EXTRA or EFFECT? (I think EXTRA is better as no one that use D::Light will use Auto_Programs (neither Auto_Program_speed which should also be classed as EXTRA and not EFFECT)).
the purpose of EXTRA is not to pollute EFFECT attribute.

D::Light now supports modes

another thing, as there's Manufacturer and Type for fixtures, there's now Mode.
for example using Briteq personality I would now set :
Manufacturer == Briteq
Type == Pro Beamer Zoom Indoor
Mode == Tour 8bit

Home can be NULL

for offset that are classed as CONTROL, I've a new Home value which is NULL.
if the offset is registered with NULL value (which is most of the time what we want) HOME won't be processed for this offset.