reimplements context_menu with jQuery
Add ng context menu
Sketch ng context menu integration (WIP)


TODOs:
- Build context-specific menu on click
- expand menu above cursor position if on bottom half of the page
Begin replacement of server-rendered context menu

Removes WorksPackages::ContextMenusController, its views and specs, and
ContextMenuHelpers.

This patch begins the work needed to serialise a given WorkPackage's
'actions' in the v3 API response, based on a user's permissions. This
should support a client-rendered context menu (or any other contextual
UI for that matter).

Much code was simply copy-and-pasted from ContextMenusController into
Api::V3::WorkPackagesController. This code still requires considerable
refactoring and optimisation.

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Remove tangential code from WorkPackagesController

This code now belongs elsewhere, e.g. ProjectsController.

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Add view spec for projects RABL templates (API v3)

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Add embedded objects to Project resource (API v3)

Initially possible_assignees, possible_responsibles and types are
needed for assembling a context menu.

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Remove unused assigns in work packages view spec

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Update ng context menu integration after customizations (WIP)
Fix test setup of ng work packages controller
Add work package table helper methods, start writing unit tests
Drop unused methods from work packages helper
Make ng-context-menu dependency explicit, fix copy & paste typo
Add work package context menu helper
Provide context menu with operations on a single work package
Add pending context menu directive test
Start dealing with bulk actions in context menu (WIP)


TODO: - get links from API
	  - dynamically insert ids of selected work packages
	  - deal with actions on associations and done ratio
Sketch inclusion of bulk links in api/v3/work_packages#index
Change wp context menu helper provider to a singleton provider
Introduce work package table service (WIP)