Refactor to use hook_link_alter

Not sure if you're interested in this, because essentially it is a full rewrite of your module, but the attached patch changes the module to use hook_link_alter instead of hook_init.

Using hook_link_alter, the links to taxonomy term pages are altered before they are rendered to the html. Advantages include:

• If you have url aliases set to the 'taxonomy/[tid]/all' links, the url alias is rendered instead of 'taxonomy/[tid]'
• Results of 'forcing' the links are cached, instead of executing hook_init on every page call even if the page is not a taxonomy term page.
• The 'non-all' pages are still available upon request
• It's an even smaller module like this ;-)