[FEATURE] Add config and use composer autoloader.

We use composer already to install SabreDAV. Include config
composer.(json|lock) to install and manage more dependencies
in future.
Also provide PSR-4 autoloading for our namespaced classes, e.g.
"Zotlabs\". To regenerate autoloader maps use:
$ composer install --optimize-autoloader --no-dev

We could also remove the whole vendor/ folder from our repository, but
that would need changes in deployment and how to install hubs and needs
more discussion first.

.gitignore

@@ -60,11 +60,13 @@ nbproject/
 .idea/
 
 
-# composer files (at the moment composer is not officially supported and only used to add SabreDAV, we should add these)
-composer.* 
-
-# When we include composer we should exclude vendor/
+## composer
+# locally installed composer binary
+composer.phar
+# vendor/ is managed by composer, no need to include in our repository
+# requires new deployment and needs discussion first
 #vendor/
-# Exclude at least some vendor test files, examples, etc.
-vendor/sabre/*/tests/
+# Exclude at least some vendor test files, examples, etc. so far
+vendor/**/tests/
+vendor/**/Test/
 vendor/sabre/*/examples/