fixed update_7018 in case of there being no changed nodes; improved default node rendering; fixed validation of expiry field

Ensure all published ads have an expiry date; added optional sitemap to allow bots to index the published propositions

Updated dependency versions in drush make. Made 'types' field non-required; fixed title on wants block;

improvements to drupal search integration; block was showing offers when should have been wants; better caching of taxonomy block; fixed node link to term page; import now includes expiry time

Allow the user to publish or unpublish on saving a proposition node; bug fixed on link to transactions; fixed problem with proposition expiry; cached category block;

improved node expiry; category block count now excludes unpublished nodes; import supports unpublished propositions; tidied up views