Bugfix: Read yaml array

Parsing an array into MapSlice results in `[{nil, nil}]`.
Parse into `[]map[interface{}]interface{}` allows for the processing of
top level arrays in the document.

Resolves: #23

examples/array.yaml

@@ -0,0 +1,9 @@
+---
+- become: true
+  gather_facts: false
+  hosts: lalaland
+  name: "Apply smth"
+  roles:
+    - lala
+    - land
+  serial: 1