zoom in and zoom out for Step
improve zoom in and zoom out when modify the content on Steps
fix #168
fix #170
fix #126
fix undefined name for a Person who dont have their name set
fix #160
upgrade keyboradjs
fix #140
fix #142
fix #143
Dried up the navbar, closes #172
Merge branch 'dev' into test_joaquin

Conflicts:
	app/assets/javascripts/bpmn.js
	app/assets/stylesheets/style.css.scss
	app/views/sandboxes/show.html.erb