Fixes ActionTracker crash on development mode

  Loads action_tracker_has_comments plugin, that dynamically adds
  comments to ActionTracker::Record, before every request in development
  mode to avoid undefined method error.

(ActionItem2728)
Merge commit 'refs/merge-requests/393' of git://gitorious.org/noosfero/noosfero into merge-requests/393
Show object in exceptions notification of feed-updater and delayed_job
filter_html: parse only sources that have macros

This solves every problem related with Hpticot breaking pages since the
parse was happening on the MainBlock too. But this does not changes the
fact tha Hpricot is currently dead and we should move on to nokogiri.

(ActionItem2873)
environment_tests: fix tests due to new enable feature save as default behaviour
profile_list_block_test: fix due to change on content_tag to tag
Merge branch 'parse-everything' into stable
Merge branch 'stable_colivre' into stable

Conflicts:
	app/models/block.rb
	test/unit/environment_statistics_block_test.rb