Heavy hook_init by default

Problem/Motivation

The pront_pdf module has an auto-configure feature - that is nice.

The problem comes that it is implemented on hook_init, and thus affects all incoming requests, generating I/O very early (by default), but on the given page the module might not be enabled at all, and the auto-config to be no needed.

Proposed resolution

As this is actually needed on node/page viewing. Move this initialization logic on hook_node_view or in an utility and call it everywhere, that renders any links for pdf printing.

Remaining tasks

Discussion, implementation. Others?

User interface changes

None - this is fully transparent.

API changes

None that I think of, except the later time that the directories are present for the PDF libraries.

Data model changes

None.