Fix dependency issue

* Fix Process() object calling
* Add PokeParent() to poke upwards
* Break linear exec chains :(

This was the issue where in a graph f1 -> f2, if you were to rm f2 &&
cat f2, then f2 would not come back because we didn't poke upwards to
refresh the timestamp. Unfortunately this adds another bug which we
solve in a later patch.

examples/graph1a.yaml

@@ -0,0 +1,22 @@
+---
+graph: mygraph
+types:
+  file:
+  - name: file1
+    path: "/tmp/mgmt/f1"
+    content: |
+      i am f1
+    state: exists
+  - name: file2
+    path: "/tmp/mgmt/f2"
+    content: |
+      i am f2
+    state: exists
+edges:
+- name: e1
+  from:
+    type: file
+    name: file1
+  to:
+    type: file
+    name: file2

examples/graph1b.yaml

@@ -0,0 +1,22 @@
+---
+graph: mygraph
+types:
+  file:
+  - name: file2
+    path: "/tmp/mgmt/f2"
+    content: |
+      i am f2
+    state: exists
+  - name: file3
+    path: "/tmp/mgmt/f3"
+    content: |
+      i am f3
+    state: exists
+edges:
+- name: e2
+  from:
+    type: file
+    name: file2
+  to:
+    type: file
+    name: file3