new feature: package level objects

tests/package_level_objects/tusefoo.nim

@@ -0,0 +1,16 @@
+discard """
+  output: '''@[(x: 3, y: 4)]'''
+"""
+
+type
+  mypackage.Foo = object
+  Other = proc (inp: Foo)
+
+import definefoo
+
+# after this import, Foo is a completely resolved type, so
+# we can create a sequence of it:
+var s: seq[Foo] = @[]
+
+s.add Foo(x: 3, y: 4)
+echo s