[vala] (10 commits) Created branch staging

[Rico Tzschichholz <ricotz src gnome org>]

The branch 'staging' was created.

Summary of new commits:

  9e9e5b5... glib-2.0: Drop g_object_unref which is part of gobject-2.0
  c28b35f... tests: Add some minimal test cases to catch insufficient he
  8260ce7... vala: Add Delegate/Method/ObjectTypeSymbol.has_type_paramet
  9c28173... vala: Use DataType.get_type_arguments()
  c263063... codegen: Add type declarations required for generics as nee
  6f5a64b... codegen: Add type declaration for errors and error domains 
  d7da53a... codegen: Add required headers for ctor/dtor of compact clas
  c1bc4ac... codegen: Improve adding of delegate target type declaration
  2ceaa53... codegen: Don't explicitly add glib headers, using symbols w
  f9b139e... codegen: Don't emit type_id for enum in non GOBJECT profile