shadow: Move cli classes into dedicated namespace.
autoloader: Cleanup old test files.

We are testing loading of old style classes differently now, so we
don't need all of them to be physically present anymore. Remove
some.
buildsystem: Remove references to application folder.
vortex: Move push notification classes into dedicated namespace.
network: Split out basic error handling into trait.
halo: Add preliminary version of a base test class.
sphere: Move Session classes into dedicated namespace.
sphere: Fix unit test dependencies.
sphere: Add missing unit test for Session->start()
halo: Fix LunrBaseTest appearing in the code coverage report.
dataaccess: Add filesystem access object class.
core: Add FrontController class.
Spawn: Rename Lunr\Spwn => Lunr\Spawn
l10n: Move code from the L10nProvider to a split out trait.
l10n: Rework L10n class.

- drop the set_language() method. This belongs into an application.
- use the L10nTrait and drop use of the Configuration class.
buildsystem: Add non-ci targets and update documentation.
core: Fix pmd issues.
halo: Fix pmd issues.
network: Fix pmd issues.
buildsystem: Adjust settings for phpmd checks.