chore: style gulpfile to order deps, config, task registration & task functions A-Z, and so that task registrations are always one liners

 Inspired by 'alphabetized one-liners' in John Papa's AngularJS Style Guide https://github.com/johnpapa/angularjs-styleguide
chore: remove bindKeys
docs: create tutorial section
docs(keyBinding): restructure markup from examples
refactor(keyBinding): move logic to controller for better testability
test(keyBinding): add some first tests
chore(README.md): add todo for updateHandler()
chore: add roadmap
chore(ROADMAP.md): move cheat sheet to v1.0
chore: add sourcemap to distribution using gulp-sourcemaps.

A sourcemap file including source contents is generated for the minified distribution file when running `gulp build_source`.
The sourcemap is now also added to the documentation assets.
Merge pull request #3 from voorhoede/sourcemaps

chore: add sourcemap to distribution using gulp-sourcemaps.
Merge branch 'master' into gulpfile-style

Conflicts:
	gulpfile.js
Merge pull request #2 from voorhoede/gulpfile-style

chore: style gulpfile to order deps, config, task registration & task functions A-Z, and so that task registrations are always one liners
refactor: more consistent API between service and directive
Merge branch 'master' of https://github.com/voorhoede/angular-key-bindings
chore: fix a few typos
chore: delete ROADMAP.md

most were done, others moved to issues
chore(README.md): add installation and tasks
chore: fix missing jshint tasks from PR #1.
Merge pull request #12 from voorhoede/jshint

chore: fix missing jshint tasks from PR #1.