Improved Dlg window pos centering
RF: tidier code for previous rating scale autodraw BF
Merge branch 'master' of git://github.com/psychopy/psychopy
BF: logging typo error
DOC: Fix typos in documentation
DOC: Fix typo in documentation

Found by LanguageTool.
Merge pull request #757 from jeremygray/master

RF: tidier code for previous rating scale autodraw BF
Merge pull request #750 from isolver/master

Improved Dlg window pos centering
Merge pull request #758 from philippwiesemann/fix-documentation-typos

DOC: Fix documentation typos