print 6.x-1.16

Fixed the problem with generating PDFs.

Changes since 6.x-1.16:

• When there's no alias defined, link to print*/nid and not print*/node/nid.
• Fix undefined offset warning in theme_print_pdf_tcpdf_header().
• #1520556 by pirog: correct typo in TCPDF non-writable dir warning.
• #1394364: only issue non-writable dir warning if PDF auto-config is enabled.
• #1516520: escape characters in print_mail update function.
• #1516198: Revert patch for #1399636, as it's not applicable to the drupal-6.x.