fixed minor issues in the documentation

- fix typo
- fix it's <=> its confusion
- format code nicely, avoid horizontal scrolling
- add missing articles
- avoid long lines
- add some punctuation
- use inline literals for variables
- whitespace
- add missing plural mark
- avoid long lines
- use inline literals for template and actions names
- add missing plural
- guess missing word
- change a to an
Granted, user starts with a vowel, but it starts with a consonant sound
(/j/) @see http://forum.wordreference.com/showthread.php?t=480322
- do not use abbreviations
- It's more suited to formal documents
- grammar
- add missing letter
- Use plural
http://www.oxforddictionaries.com/words/he-or-she-versus-they
- replace saxon genitive with pural
- use inline literals for event names
- use plural
- use inline literals for variables
- whitespace
- add missing word
- move word
- add missing words
- deobfuscate code
Merge pull request #2259 from greg0ire/doc_improvements

Finished proofreading the book. Say squash if it's ok.