Add example to test the Python module being renamed to __init__.py

This examples tests the SWIG generated module being placed into a directory and
then renamed __init__.py to convert the module into a package. This ability
stopped working in swig-3.0.9. However, only Python 2.7 or 3.3 and later work. If
Python 3.2 support is needed, use moduleimport in %module to customise the import
code.

Issue #1282

Examples/python/import_packages/module_is_init/runme.py

@@ -0,0 +1,26 @@
+import os.path
+import sys
+
+# Test import of a SWIG generated module renamed as the package's __init__.py
+testname = os.path.basename(os.path.dirname(os.path.abspath(__file__)))
+print "Testing " + testname + " - module renamed as __init__.py"
+
+if sys.version_info >= (3, 0, 0) and sys.version_info < (3, 3, 0):
+    print "  Not importing as Python version is >= 3.0 and < 3.3"
+    # Package detection does not work in these versions.
+    # Can be fixed by using this in the interface file:
+    #   %module(moduleimport="from . import $module") foo   # without -builtin
+    #   %module(moduleimport="from .$module import *") foo  # with -builtin
+    sys.exit(0)
+
+import pkg1
+print "  Finished importing pkg1"
+
+if pkg1.foofunction(123) != 1230:
+    raise RuntimeError("foofunction failed")
+
+fc = pkg1.FooClass()
+if fc.foomethod(1) != 6:
+    raise RuntimeError("foomethod failed")
+
+print "  Finished testing pkg1"