listboxservice: Render picons a bit smaller

Picons are usually about 3:2 in size, or even 100:70, not likely 2:1.
So reserve 1.5*height for the icon area.
gdi/gpixmap: Implement software scaling

Not all hardware supports alphablending and/or scaling, so implement
a simple software version. Also, the software version is faster for
small images (e.g. 50x50 pixels or so) because of the overhead of
setting up hardware blitting (see previous commits on this file).
listboxservice: On closer inspection, picons are 5:3

The ocram sets use 100:60 sized, and since the skins usually don't
taks aspect ratio into account, 5:3 should be "just right". Thus
no background.
listboxservice: do not keep aspect ratio anymore

As the target has already the expected aspect ratio keeping the
aspect ratio is not required anymore. So currently it can always
be scaled without having blackfilled borders.
It might have  a disadvantage with picons that big differ from the
usual picon relations.
In addition add a margin of 8 to the service name so the service
name is not "glued" to the picon.
Merge branch 'master' of git://git.code.sf.net/p/openpli/enigma2
fix po