User-defined WMS SRS setting for custom projections

[anonymous]

Custom Projection has no means to provide a setting for the user-defined WMS SRS,
so i have written this patch creating a +wmssrs=EPSG:123456 parameter:

src/org/openstreetmap/josm/gui/preferences/projection/CustomProjectionChoice.java

@@ -187 +187 @@
             s.append("    "+tr("Built-in:")+" ");
             s.append(listKeys(Projections.nadgrids)+"<br>");
             s.append("<b>+bounds=</b>minlon,minlat,maxlon,maxlat - <i>"+tr("Projection bounds (in degrees)")+"</i><br>");
+            s.append("<b>+wmssrs=</b>EPSG:123456 - <i>"+tr("WMS SRS (EPSG code)")+"</i><br>");
 
             return new HtmlPanel(s.toString());
         }

src/org/openstreetmap/josm/data/projection/CustomProjection.java

@@ -68 +68 @@
         no_defs("no_defs", false),
         init("init", true),
         // JOSM extension, not present in PROJ.4
+        wmssrs("wmssrs", true),
         bounds("bounds", true);
 
         public String key;
@@ -151 +152 @@
             if (s != null) {
                 this.bounds = parseBounds(s);
             }
+            s = parameters.get(Param.wmssrs.key);
+            if (s != null) {
+                this.code = s;
+            }
         }
     }