Improve context-inspector widget
New class: Wirecloud.ContextManager
Remove current support for context providers
Initial rewrite of the context support
Notify context changes using the old EzWebAPI
Fix regression in the old EzWebAPI: redirect user_name to username
Remove context listeners when iwidgets are unloaded
Merge branch 'feature/new-context-support' into develop

Conflicts:
	src/wirecloud/platform/static/iphone/opManager/Workspace.js