Gateway: add a getShortName for use with scripting

When the gateway is a variable somewhere, it is convenient
for its name to be as short as possible. E.g.:

* "SciJava" can be "sj"
* "ImageJ" can be "ij"

It is handy for each gateway to self-suggest such a name.

Author: ctrueden

src/main/java/org/scijava/AbstractGateway.java

@@ -87,6 +87,11 @@ public AbstractGateway(final String appName, final Context context) {
 
 	// -- Gateway methods --
 
+	@Override
+	public String getShortName() {
+		return getClass().getName().toLowerCase();
+	}
+
 	@Override
 	public <S extends Service> S get(final Class<S> serviceClass) {
 		return context().service(serviceClass);

src/main/java/org/scijava/Gateway.java

@@ -118,6 +118,12 @@
  */
 public interface Gateway extends RichPlugin, Versioned {
 
+	/**
+	 * Gets a very succinct name for use referring to this gateway, e.g. as a
+	 * variable name for scripting.
+	 */
+	String getShortName();
+
 	/**
 	 * Returns an implementation of the requested {@link Service}, if it exists in
 	 * the underlying {@link Context}.

src/main/java/org/scijava/SciJava.java

@@ -112,4 +112,11 @@ public SciJava(final Context context) {
 		super(SciJavaApp.NAME, context);
 	}
 
+	// -- Gateway methods --
+
+	@Override
+	public String getShortName() {
+		return "sj";
+	}
+
 }