Make ChainRouter work with PHP 7.2

[dkreuer]

Currently the chain router fails in symfony context with

In ChainRouter.php line 101:
                                                                                       
  [Symfony\Component\Debug\Exception\ContextErrorException]                            
  Warning: count(): Parameter must be an array or an object that implements Countable

This is because the sortedRouters property is not initialized.

The change proposes to take the not initialized property into account while fetching all routes.

[dbu]

this has been fixed in #200 already. i then wanted to actually test that everything works with php 7.2 before tagging a release, but got sidetracked by things not working in one of the phpcr dependencies. (phpcr/phpcr-utils#174 if you are curious). as that problem is not trivial to figure out, and we already claim to be compatible with php 7.2, i will just tag 2.0.2 now as its definitely an improvement.

[dbu]

2.0.2 is now tagged

[dkreuer]

Thank you very much.