Prepare release 0.12.1

[ricardograca]

Changelog:

• Lots of documentation fixes and updates:
  • Fix incorrect value of second argument to model event handlers: Fix documentation of some events #1723
  • Fix incorrect return value from .detach(): Fix incorrect documentation for detach() #1720
  • Fix incorrect return value from model.has(): Fix doc for model.has return values #1712
  • Fix fetching:collection and fetched:collection not being generated or visible on the navigation bar: Fixes Model fetchAll event documentation #1114
  • Update contributing document and issue templates: Update contributing document and issue templates #1736
  • Add more information and links to Parse and Format docs: Improve Parse and Format docs #1727
  • Add bookshelf-ez-fetch to Community Plugins: Add bookshelf-ez-fetch to Community Plugins #1708
  • Add bookshelf-default-select to Community Plugins: Add bookshelf-default-select to Community Plugins #1706
  • Add information and examples about calling super() on model's initialize(): Document calling super() on initialize(). #1529
  • Add npm version badge to readme: f4dd792
• Fix inability to attach belongsToMany relation to models fetched with fetchAll(): Fix for issue #629 #1716
• Fix foreign key = 0 not fetching related object: Fix foreign key = 0 not fetching related object #1639
• Fix unparsed previousAttributes for related models: Ensure previousAttributes are parsed after eagerPair #1457
• Update some dependencies: Update eslint to the latest version 🚀 #1734, Update uuid to latest version #1733, Update bookshelf-jsdoc-theme to the latest version 🚀 #1732, chore(package): update sinon to version 4.1.3 #1728, fix(package): update chalk to version 2.3.0 #1726

Full changelog