Adding README and instructor notes for new Python with ipythonblocks section.

This section will cover teaching basic Python via ipythonblocks.
Adding ipythonblocks module at version 1.5.
Adding material related to introducing students to RGB colors.
Adding material for "Playing with Blocks" section.

This section covers introductory Python such as indexing, variables,
for-loops, if-statements, and slicing.
Adding material for the "Building Blocks" section.

This section covers reading files and working with lists and strings.