Add a README to shapefile_parser/.

shapefile_parser/README.md
	-Add a README that describes the contents of the
	`shapefile_parser` project, and how one can use it via both the
	command-line and as a module import.
Add READMEs to hash algorithms/polynomial interp.

algorithms/hash_algorithms/README.md
	-Add a README listing the algorithms implemented (and the
	corresponding file for each).

algorithms/polynomial_interpolation/README.md
	-Add a README describing what the project implemented, how
	functionality is divided between `polynomial_interpolation.py`
	and `animation.py`; link the three gifs in `animation/`.
Add msg to polynomial-interp unit-test, mod README.

algorithms/polynomial_interpolation/polynomial_interpolation.py
	-Add a statement to `test_polynomial_interpolation()` that
	prints an explanatory message upon successful completion of the
	unit-test, because otherwise there isn't any output and it's
	unclear what happened.
Add a README to least_squares_estimation.

algorithms/hash_algorithms/README.md
	-Add a brief description of how to execute each file, and what
	output to expect.

algorithms/least_squares_estimation/
(README.md, least_squares_estimation.png)
	-Add `least_squares_estimation.png`, the image generated by
	`demo.py`.
	-Add a README summarizing the contents of
	`least_squares_estimation/`: includes a link to the wikipedia
	article about the algorithm, and display
	`least_squares_estimation.png`.
Add a README to the sorting algorithms.

algorithms/sorting/README.md
	-Add a README describing which sorting algorithm is implemented
	in which file, with a hyperlink to the relevant wikipedia
	article for each.
Add a README to polynomial_roots.

algorithms/polynomial_roots/README.md
	-Add a README clarifying what `polynomial_roots.py` implements,
	and what it outputs when executed.
Add a README to singly_linked_list/.

data_structures/singly_linked_list/README.md
	-Add a README to the `singly_linked_list/` project. Explain what
	the project implements, describe valid `make` targets, and
	provide an example of inclusion and usage in another C file.
Add a README to doubly_linked_list/.

data_structures/doubly_linked_list/README.md
	-Add a README to the `doubly_linked_list/` project. Explain what
	it implements, describe valid `make` targets, and provide an
	example of inclusion and usage in another C file.
Add a README to circular_singly_linked_list/.

data_structures/circular_singly_linked_list/README.md
	-Add a README to the `circular_singly_linked_list/` project.
	Explain what it implements, describe valid `make` targets, and
	provide an example of inclusion and usage in another C file.
Add a README to stack/.

data_structures/stack/README.md
	-Add a README to the `stack/` project. Explain what it
	implements, describe valid `make` targets, and provide an
	example of inclusion and usage in another C file.
Add a README to queue/; mod comment in queue.h.

data_structures/queue/README.md
	-Add a README to the `queue/` project. Explain what it
	implements, describe valid `make` targets, and provide an
	example of inclusion and usage in another C file.

data_structures/queue/src/queue.h
	-Remove all the trailing asterisks from the documentation
	comment for `printQueue()` and indent its contents, in
	keeping with the style of all the other comments in the file.
Add READMEs to algorithms/ and data_structures/.

(algorithms, data_structures)/README.md
	-Add READMEs describing the contents of each directory.
Merge branch 'documentation' into develop

(algorithms, data_structures)/*/README.md
	-Add READMEs to all completed projects, explaining their
	contents and illustrating sample usage.
	-Anything implemented from this point onward will get its own
	documentation README at the time of completion.