Update Route.php to allow attach with empty path

When using attach, it's not possible to add a route that uses the path_prefix provided in attach without a trailing slash. If the path itself is left blank, the path_prefix is ignored and the route used during matching is blank. With this modification, it will match on the route so for instance $router->attach('/blog', [ 'routes' => [ 'browse' => '' ] ]); will allow the route '/blog' to be matched. Without this, the route has to be '/blog/' with a trailing slash.
Add 5.5 to travis
add __isset(); fixes #30
Merge branch 'develop' of github.com:auraphp/Aura.Router into develop
Merge pull request #25 from pokmot/develop

Update Route.php to allow attach with empty path
fix highlighting and syntax errors
add travis build status badge
update license
update changes
updated composer
update composer with version 1.1.1
Merge branch '1.1.1'