Fix "Arcade" breadcrumb link

The "Arcade" breadcrumb link (at the upper left of most pages) previously
pointed to [hostname]/site/arcade, rather than the actual location
[hostname]/[baseURL]/index.php/site/arcade. In the case of the default build,
this base URL is "mg-game/www", but the fix allows for any base URL.

Note: the two different modified files are identical except for the line
endings - one uses Unix-style endings while the other uses Windows-style
endings. This will be addressed in a future commit.