Merge branch 'master' of git://github.com/psychopy/psychopy

# By Mark Hymers (9) and Jonathan Peirce (4)
# Via Jonathan Peirce
* 'master' of git://github.com/psychopy/psychopy:
  BF: dual screen option was not working under linux (thanks Robert Muil)
  DOCS
  Add changelog entry
  Cleanup left over port objects
  Place files in parallel/ directory
  Get logic right way round
  Sort out documentation for parallel refactor
  Add readData routine
  DOCS: minor
  ENH: slightly quicker to delete the contents of a list than delete the list (thanks Sol)
  Refactor parallel port access to use classes instead of globals.
  Add psychopy API compatible wrapper for inpout32
  Add abstraction layer to allow parallel use on linux

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RF: streamlined checking of constant fields in components
DOC: changelogs