Renamed WMGetApplicationIconBlendedPixmap() to

Renamed WMGetApplicationIconBlendedPixmap() to
WMCreateApplicationIconBlendedPixmap() to avoid confusion.
This is because this function does generate a new WMPixmap from the
available icon image by combining it with the specified color and you
need to call WMReleasePixmap() on the generated pixmap after you're
done with it.
This is unlike the case of WMGetApplicationIconPixmap() where it just
returns a pointer to the existing application icon pixmap that was set
before and where you don't need to release it after you're done working
with it.
To avoid this confusion about when you need to release and when not,
one is using Get (get existing, no release needed), while the other is
now using Create (generate a new pixmap, release required) in their
name.

Since this change was made to a function that was just added to the API
in the previous commit, no modification is needed to the existing
applications that use WINGs.