Config file 'none' results in no user config

When the `none` value is provided for the configuration parameter
should no user-specific configuration be loaded. Due to a logic error
this would cause a crash.

This commit remedies that issue by changing the involved business
logic to work as expected.
Packages should inherit

There was an issue where packages did not inherit correctly;
I have solved this by adding the following rule:

    If a descriptor's package equals the root package then
    that indicates that the package was not specified. In which
    case you go through all parents to see if a package was
    specified and use that.
Inheriting methods from interfaces

The method inheritance did not find methods that should be inherited from
extended interfaces and implemented interfaces. This commit fixes that issue
and introduces a caching variable for inherited methods so that it does not
have to re-scan continuously.
Fix and improve broken behat tests
Merge branch 'feature/1268' into end-to-end-with-behat
Merge branch 'develop' of github.com:phpDocumentor/phpDocumentor2 into end-to-end-with-behat

Conflicts:
	src/phpDocumentor/Parser/Command/Project/ParseCommand.php
Add verification that the test ran as expected
Fix test after type collection refactoring
Fix syntax error in example
User-specific configuration was not loaded

During the recent refactoring of the configuration system the --config
and -c options no longer worked because of an error in the loading
of said configuration. This commit resolves that bug
Assembling a method crashes

The ArgumentAssembler that is injected sometimes has no builder set.
When this is the case the processing of a method will crash. This
behaviour change was introduced during a recent refactoring where the
construction of said assembler was moved to the container.

To solve this we verify that a builder is set on the argument assembler
and should it be missing we just set the current builder of the method.
These should always be the same so we can do this without a problem.
Parsing crashes on visibility as string

Sometimes the visibility can be returned as a(n empty) string; this
causes the succeeding foreach loop to crash. To make sure this error
doesn't happen we explicitly cast the retrieval of the visibility to
array; should a string be returned it will be automatically encapsulated
in an array.
Routing crashes in Twig

Apparently the twig extension always expects a method
`convertToRootPath` in the extension class; despite that the callback
points to the Route Renderer object.

I couldn't find the cause of this behaviour in time so as a workaround
I added a method `convertToRootPath` that proxies to the Route Renderer.

Perhaps we can find the cause and remove this proxy method in the
future.
Fix last broken features and a bug
Merge branch 'develop' of github.com:phpDocumentor/phpDocumentor2 into update-behat-tests
Fix broken test
Re-enable behat in Travis
Update contribution guide to match new XHGUI
Updated lock file
Merge pull request #1304 from mvriel/update-behat-tests

Fix and Update Behat tests