Add reference to Prasetya mailing list item.
Add reference to Proving an implication via its converse.
Add note about union - find algorithm.
Add reference to NYU course.
Add reference to errata for Pelletier
Add reference for "On an exercise of Tony Hoare's"
Add reference for Pelletier problems.
spelling
Remove extra line.
Modify debug steps.
Format lines correctly.
Updated Usage Notes (markdown)
Simplify debugging with FSI by using FSI option use:
Add section on how to debug a single example.
Change solution to parse error using verbatim string.
Added section explaining reasons for stack overflows when running examples.
Create usage notes page. Note work around to use space with end-of-line.