This reverts commit 9e98109b.

This prevents a lot of -dev dependencies in composer.lock which are
not used otherwise and generate 'scary' warnings like "Package x is
abandoned".

Closes #718

This reverts commit b9f92f33.

This reverts commit 82a46a7c.

This removes the dependency on mcrypt for good, closes #660 and resolves #615.

I believe #592 broke unit tests by adding a dev-dependency to
`composer.json` but forgot to update `composer.lock`. Therefore,
`composer install` does not install all the necessary dependencies for
tests.

This enables too the implementation of additional contact attributes, as requested in #509 to support the SIRTFI framework.

Update test notes to point to the 4.8 documentation and describe
how to run an old version of phpunit from composer's bin dir.

Now that the SAML2 library has been updated to use the new SimpleSAML\Logger, we can update the dependency here. Since both libraries are interdependent, we are pointing to a specific commit in master, aliasing it to 2.2. That way we can keep business as usual for any other package which may depend on 2.2, while getting the changes into SimpleSAMLphp.

Now we are finally using the 2.x branch of the SAML2 library, which was also migrated to use namespaces. Even though the library provides an autoloader that allows loading the classes with the old names using class aliasing, we need to do the migration in one commit (at least for most part of it). This is due to the way SimpleSAMLphp checks data types, using inheritance to check objects agains abstract or more general classes. Even though class aliasing works, there's no way to replicate those relationships, and type checks that use the old class names will fail because the aliases are virtually new classes that don't inherit from others.