Adding ipborg dependencies to readme.
Added function for getting specified code cells from Ipython.
Added _to_simple_grid for JSON-izing grids.
Function for posting grids to ipythonblocks.org.
Add __eq__ method to BlockGrid for easier testing.
Added class method for creating a BlockGrid from an ipythonblocks.org grid ID.
Added class method for creating an ImageGrid from an ipythonblocks.org grid ID.
Terminate execution on HTTP errors.
table_data -> grid_data
Refactor post request construction into its own method.
Add secret kwarg to from_web methods for retrieving secret grids.
Add ipythonblocks.org to README.
Switch to setuptools so we can list requests as a requirement.