Add "show" optional parameter to cite method

By default calling ij.py.cite() will print the citation to the console.
If set to False the citation string will be returned without calling
print().

Author: elevans

src/imagej/__init__.py

@@ -164,12 +164,14 @@ def argstring(self, args, ij1_style=True):
                     formatted_args.append(arg)
             return " ".join(formatted_args)
 
-    def cite(self) -> str:
+    def cite(self, show: bool = True) -> str:
         """Generate a citation string and package version numbers.
 
         Generate the PyImageJ citation/reference string and fetch
         the environments Python and Java versions.
 
+        :param show: Print the PyImageJ citation if True, if False
+            the PyImageJ citation string is returned instead.
         :return: A citation and package version numbers
         """
         # set PyImageJ reference sub strings
@@ -194,7 +196,10 @@ def cite(self) -> str:
             + python_version
             + java_version
         )
-        return citation
+        if show:
+            print(citation)
+        else:
+            return citation
 
     def dtype(self, image_or_type):
         """Get the dtype of the input image as a numpy.dtype object.