Several small bug fixes
- Fix dockerbuild permission issue
- The true value of the PDF_DEMO_LINK option was not working
- metadata: the variable maxSize was not defined
- Message to inform that in private browsing mode (on firefox) the application does not work because opening the cache is impossible
Contributors : @xgaia @gpoma @milouse @wincelau
Full Changelog: v1.3.0...v1.3.1