pagination: avoid counting pages outside searches.

Replace this common pattern in controllers:

    @tags = Tag.search(search_params).paginate(params[:page], :limit => params[:limit], :search_count => params[:search])

with this:

    @tags = Tag.paginated_search(params)

`search_count` is used to skip doing a full page count when we're not
doing a search (on the assumption that the number of results will be
high when not constrained by a search). We didn't do this consistently
though. Refactor to do this in every controller.

app/controllers/note_versions_controller.rb

@@ -2,7 +2,7 @@ class NoteVersionsController < ApplicationController
   respond_to :html, :xml, :json
 
   def index
-    @note_versions = NoteVersion.search(search_params).paginate(params[:page], :limit => params[:limit])
+    @note_versions = NoteVersion.paginated_search(params)
     @note_versions = @note_versions.includes(:updater) if request.format.html?
     respond_with(@note_versions)
   end