Expands tutorial macro section with step by step guide.
Modifies example to use splitLines.
Corrects grammar and span of italics in text.
Adds to tutorial info about unpacking tuples.
Adds an example to htmlparser showing how to save changes.
Mentions tuple unpacking only works in var/let blocks.
Merge pull request #695 from gradha/pr_adds_htmlparser_example

Adds an example to htmlparser showing how to save changes.
Merge pull request #687 from gradha/pr_documents_tuple_unpacking

Adds to tutorial info about unpacking tuples.
Merge pull request #676 from gradha/pr_expands_macro_tutorial

Expands tutorial macro section with step by step guide.