Two new hidden prefs:
-allow user to display locale date/time in the notes containing the extracted annotations;
-allow user to change the quotation marks in these notes (cf. http://forums.zotero.org/discussion/27456).
hidden prefs:
-locale date in extracted notes is the default;
-cleaning the code for quotation marks in these notes.
Merge pull request #69 from gracile-fr/pdfExtraction.HighlightQuotationMarks

Two new hidden prefs