Feature: Dashboard

Fixes #37:

> Angles (the views on ideas in the top bar) are confusing to users; they expect them to
> reflect states while I excepted them to reflect "outstanding actions to be taken".
> 
> They're quite redundant with the Kanban view, too.
> 
> - add a filter dropdown to show only a given idea state (this would also switch to the cards view if on the board view).
> - remove all angles but "all ideas" and "followed"
> - add a "dashboard" toplevel item and assorted Dashboard view
> - post-login landing page is the Dashboard
> 
> The dashboard is to show "oustanding actions" based on your role:
> 
> - Ideas to size (5 most recently active / MRA) if PM or Architect
> - Ideas to vet (5 MRA) if PM or Architect
> - The above replaced with 5 MRA ideas if other role
> - 5 random votable ideas
> - 5 most recently sumbitted
> - "current projects" working set if PM (ideas from picked to signed off)
> - Ideas to approve or sign off if BD
> - 5 most recent notifications
> - 5 most recent comments on followed ideas
> - "show all" link on each block