Allow full stops in route parameters

[AliceKLWilliams]

Uses the suggested fix in https://github.com/dannyvankooten/AltoRouter/issues/221#issuecomment-424599922 in order to allow the router to parse param values with dots.

We will need to consider the implications of this, as the comment mentions that it ignores full stops so that you can ignore file extensions in URLs. This MR causes some behaviour changes:

Previously

/route/{id} with route/file.txt would not match at all.

Now

/route/{id} with route/file.txt would match, and id would be mapped to file.txt.