[FIX] Update README for master
[IMP] l10n_pl: some corrections in Polish CoA

PLN as default currency
Many improvements in taxes and fiscal positions
Fixes #825
[ADD] web_pdf_viewer: PDF in-browser preview

This module extends web client and reporting tool in order to allow a
preview of PDF files directly in the browser (if supported by the
browser). If you disable it, standard file download stays available.
[FIX] google_calendar: browse user as SUPERUSER_ID to be able to write/update google_calendar info on user
[FIX] web_tip: scroll if needed prior to displaying a tip
[IMP]event:improvement event_kanban view and on card global click redirect to frontend and add new type (url)