Merge pull request #183 from pedropark99/dev-0.15

Update book code examples to Dev 0.15

Merge pull request #170 from pedropark99/dev-epub

Add epub format configs

Add contributor

Merge pull request #152 from pedropark99/dev-modules

Add new section to explain pub keyword

Merge pull request #132 from pedropark99/edition-2

Add links for Leanpub publishing

Update contributors list

Add more contributors to list

Merge pull request #99 from pedropark99/improve-engine

Fix duplicated results from stderr

Add @vedang to contributors list

Fix readme