Wayfinder document variables + WebLogin @FILE ability for &tpl

Wayfinder:
Since Wayfinder is not able to use all document variables like [+longtitle+] or [+pagetitle+] in templates, I added the little feature, that makes all document variables usable the same way like template variables.
Also added the ability to handle @INHERIT for tvs (like in ditto).

WebLogin:
Added the feature to use files as Templates with the &tpl=`@FILE path/to/filename` parameter.