[WMS] STYLES parameter required in WMS 1.1.x requests

[dmorissette]

As it is now, MapServer doesn't include the STYLES parameter in the GetMap URL 
request if it's missing.  STYLES is a required parameter, and can be passed as 
'STLYES=' (empty) to request default styles.

MapServer should check if a STYLES parameter was included in the CONNECTION 
string, and if not then add one.

[dmorissette]

Fixed.  This is handled properly in the V4.0 mapwmslayer.c ... if you use the 
metadata way of passing WMS connection parameter then STYLES=... will always be 
set.  

If you use the old/deprecated way in which the CONNECTION value contains all the 
parameters (VERSION, LAYERS, etc.) then STYLES has to be included as well.