Update package to include new API and expanded documentation

[stsci-hack]

A slightly new API has been added to provide an interface for running the drizzle and blot routines. The new APIs allow the user to call the drizzle and blot functions without needing to provide any WCS objects, instead relying on providing a pixmap computed by the user using the input WCS objects. The original functions have been retained to provide a more seamless transition to the new APIs.

The documentation has also been expanded to not only describe the algorithms in some additional detail, but also to add a page dedicated solely to describing how to call the code. The new user doc page provides examples of how to call the code for both HST and JWST data with descriptions on how to call it for nearly any data using the HST and JWST examples as templates.