build the imap client as shared .so
update libxml2 and libxslt to their latest versions
update postgresql to 9.3.5
downgrade to libxml 2.7.8 to avoid compatibility problems with os x apache
Merge remote-tracking branch 'origin/5_4_mountainlion' into 5_4_yosemite

* origin/5_4_mountainlion:
  downgrade to libxml 2.7.8 to avoid compatibility problems with os x apache
  update postgresql to 9.3.5
  update libxml2 and libxslt to their latest versions
  build the imap client as shared .so