fixes for disabled slashUrls + multilang

Please check if this is the correct/best solution, i'm new at pw.

Problem 1:
multilang support with page names installed and slashUrls disabled
> admin > Pages >Settings tab

english
/en/aboutwhat

...same for other languages

fix: line 356 if we are in admin do not strip the trailing slash 

Problem2:
if homepage tpls have slashUrls disabled, links in navigation should have href(s) like:

site.tld/it
site.tld/fr
site.tld/es

instead of

site.tld/it/
site.tld/fr/
site.tld/es/

fix lines-335-337
BTW, should we leave the slash for the default language homepage (line 335)

kind regards