Fix issue scijava#406 without a location call handler supportsOpen(st…

…ring)

This commit fixes an issue caused by calling the Location version of the
method supportsOpen() in all cases when many IOPlugin do not yet
implement that Location version of that method and therefore always
return false. Instead now IOService getOpener(string) directly calls the
string version of supportsOpen. This ensures older IOPlugin that can
support the file provided are discovered and used.

src/main/java/org/scijava/io/IOService.java

@@ -50,7 +50,10 @@ public interface IOService extends HandlerService<Location, IOPlugin<?>>,
 	 * location.
 	 */
 	default IOPlugin<?> getOpener(final String source) {
-		return getOpener(new FileLocation(source));
+		for (final IOPlugin<?> handler : getInstances()) {
+			if (handler.supportsOpen(source)) return handler;
+		}
+		return null;
 	}
 
 	/**