staticDir doesn't work if it ends with /

[timotheecour]

if staticDir is /foo/bar/ and there's a file in /foo/bar/baz.txt, a request for /baz.txt won't succeed.
(it works if staticDir is /foo/bar)

either jester should call doAssert staticDir == staticDir.normalizedPath somewhere in the code (where all code paths lead to) or allow it, as done in #197