cleanup of the show-completed / show-remaining. That context-dependant

/ display-context-for stuff was bugging me out, and wasn't using Derby
to it's potential. also some tags & habit-wide cleanup in helpers:taskClasses()

src/app/helpers.coffee

@@ -125,14 +125,17 @@ viewHelpers = (view) ->
   ###
     Tasks
   ###
-  view.fn 'taskClasses', (task, filters, dayStart, lastCron) ->
+  view.fn 'taskClasses', (task, filters, dayStart, lastCron, showCompleted=false) ->
     return unless task
     {type, completed, value, repeat} = task
 
+    # completed / remaining toggle
+    return 'hidden' if (type is 'todo') and (completed != showCompleted)
+
     for filter, enabled of filters
       if enabled and not task.tags?[filter]
         # All the other classes don't matter
-        return 'hide'
+        return 'hidden'
 
     classes = type
 
@@ -150,6 +153,8 @@ viewHelpers = (view) ->
         classes += " completed"
       else
         classes += " uncompleted"
+    else if type is 'habit'
+      classes += ' habit-wide' if task.down and task.up
 
     if value < -20
       classes += ' color-worst'

src/app/tasks.coffee

@@ -99,28 +99,8 @@ module.exports.app = (appExports, model) ->
     chart = new google.visualization.LineChart(document.getElementById( chartSelector ))
     chart.draw(data, options)
 
-  appExports.changeContext = (e, el) ->
-    # Get the data from the element
-    targetSelector = $(el).attr('data-target')
-    newContext = $(el).attr('data-context')
-    newActiveNav = $(el).parent('li')
-
-    # If the clicked nav is already active, do nothing
-    if newActiveNav.hasClass('active')
-      return
-
-    # Find the old active nav and context
-    oldActiveNav = $(el).closest('ul').find('> .active')
-    oldContext = oldActiveNav.find('a').attr('data-context')
-
-    # Set the new active nav
-    oldActiveNav.removeClass('active')
-    newActiveNav.addClass('active')
-
-    # Set the new context on the target
-    target = $(targetSelector)
-    target.removeClass(oldContext)
-    target.addClass(newContext)
+  appExports.todosShowRemaining = -> model.set '_showCompleted', false
+  appExports.todosShowCompleted = -> model.set '_showCompleted', true
 
   setUndo = (stats, task) ->
     previousUndo = model.get('_undo')