missing wagtailimages_tags

Event Pages give a 500 error when page has a speaker image because the page uses the image template tag  {% image speaker.image width-200 %}.

Loads wagtailimages_tags
Merge pull request #40 from huxley/patch-1

missing wagtailimages_tags
fix tag imports in event_page.html
specify wagtail 0.6 in requirements
fix import of register_signal_handlers from wagtailsearch
Django 1.7 support