Merge pull request #55 in TPSH/ckanext-odsh from dev to master

* commit '982c0e4c': (60 commits)
  adds README
  fixes bug in footer.html
  fixes bug, date in filter list was invisible in IE
  fixes margin in password reset form
  adds aria role menuitem to user dropdown menu
  improves accessibility
  adds alt-text and aria-hidden to category items in search results
  adds skiplink, adds empty alternative text to category items
  bugfix thumbnail to many values
  bugfix tools
  replaces dict by OrderedDict for SUBJECT_MAPPING, adds tests
  adds unit tests for get_subject_for_selection
  changed req
  fixes import bug
  fixes bug in css introduced by commit  64813bcd
  new
  changed to pdftotext
  minor changes, code style
  changed thumbnail
  css
  ...