We are in the process of making possible for users to save a PDF or XHTML version of the wiki or certain namespaces. The whole thing is not yet fully implemented but visitors and members can save the wiki page they are on to PDF with the option on the right menu.
Bulk PDF export is functional but not yet available and XHTML export work only for a small amount of pages or individual ones. More work need to be done before making both options available. A download link for each will be on this page and updated regularly.
The only thing the offline version does not contain is the wiki downloadable documents and utilities. However wiki images are included and sound files too (XHTML version only). All internal and external links to resources are fully working, as long as the document or utility will be hosted at the url specified in the offline version.
Full wiki (2017/04/08): PDF Version