Apply sld names layer on all layers of the same group

[assefa]

Initial request from Richard E Brown (reb@usgs.gov)

We have a number of data layers separated by state that we are associating
together as a single referenced GROUP layer in a map file.  We hoped the
SLD could then reference only the GROUP name rather than each of 50 state
layer names but we get blank images back. If we change the SLD NamedLayer
Name to a state name it works fine but doesn't seem to recognize the GROUP
name as applying to the individual layers.  Could this be a bug in the
program logic or is this expected behavior?

[assefa]

Changes are minimal : the SLD names layer is compared to group name (after 
layer's name and layer's wms_name).

I had sent the path to Richard for testing and It seems to work properly.

Commiting the path and marking it as Fixed.