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.

This branch contained some refactoring to move some of the View
class's loading logic into the Renderer class.  This will help
going forward as we change the Loader class.

This will help with future refactoring and code maintenance by not
having the same logic duplicated in more than one part of the code.
It also takes more responsibility away from the View class, which
is what we want.

This commit also adds a Renderer.read() method and a file_encoding
keyword argument to Renderer.__init__().

Created a Reader class to encapsulate reading files with the encoding
and decode_errors attributes.

The spec tests are now excluded from nosetests, by default.  Added
instructions to the README on how to include them.