Also, more progress on view.Locator.get_template_path().

Changed make_template_name() from a function into a method.  Moved
the search_dirs argument from a Locator constructor argument to
an argument of Locator.locate_path().

Now the class no longer has an indirect dependency on the Reader class.

This further trims down the View class.

Also simplified the Template.load_template() method.

The constructor accepts search_dirs, template_encoding, and template_extension.