Fixes #993: Windows filenames do not support UTF-8

Windows makes use of ASCII as their encoding for files and folder names and does
not support the use of UTF-8 (http://stackoverflow.com/questions/2050973/what-encoding-are-filenames-in-ntfs-stored-as). This commit
fixes support for that in the Twig and Routing component.
#993: ExternalRouter's scheme is encoded
Merge pull request #1266 from mvriel/feature/993

Fixes #993: Windows filenames do not support UTF-8