DefaultModuleService: respect item's default value

When calling ModuleService#getDefaultValue(ModuleItem), if the
ModuleItem in question has an explict default value -- as obtained
from the new ModuleItem#getDefaultValue() accessor -- then that
value should take precedence over any other possibility.

Author: ctrueden

src/main/java/org/scijava/module/DefaultModuleService.java

@@ -302,6 +302,8 @@ public <T> T load(final ModuleItem<T> item) {
 
 	@Override
 	public <T> T getDefaultValue(final ModuleItem<T> item) {
+		final T defaultValue = item.getDefaultValue();
+		if (defaultValue != null) return defaultValue;
 		final T min = item.getMinimumValue();
 		if (min != null) return min;
 		final T softMin = item.getSoftMinimum();