Merge pull request #27 from ThyArmageddon/master

PIP8 Typo Fixes
Adds with statement in the file chapter.
Adds initial text on testing chapter, needs lot of rewriting.
Adds testing chapter for the first time.
Updates HTML theme of the book.
Updated github text to pym.
Adds collection module back.
Index items for class chapter.
Index items for collections chapter.
Index items for datastructure chapter.
Index items for exceptions chapter.