Mega patch

This is still a dirty prototype, so please excuse the mess. Please
excuse the fact that this is a mega patch. Once things settle down this
won't happen any more.

Some of the changes squashed into here include:
* Merge vertex loop with type loop
(The file watcher seems to cache events anyways)
* Improve pgraph library
* Add indegree, outdegree, and topological sort with tests
* Add reverse function for vertex list
* Tons of additional cleanup!

Amazingly, on my first successful compile, this seemed to run!

A special thanks to Ira Cooper who helped me talk through some of the
algorithmic decisions and for his help in finding better ones!

examples/graph3a.yaml

@@ -0,0 +1,44 @@
+---
+graph: mygraph
+types:
+  noop:
+  - name: noop1
+  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
+  - name: '@@file3'
+    path: /tmp/mgmt/f3
+    content: |
+      i am f3, exported from host A
+    state: exists
+  - name: '@@file4'
+    path: /tmp/mgmt/f4
+    content: |
+      i am f4, exported from host A
+    state: exists
+collect:
+- type: file
+  pattern: ''
+edges:
+- name: e1
+  from:
+    type: noop
+    name: noop1
+  to:
+    type: file
+    name: file1
+- name: e2
+  from:
+    type: file
+    name: file1
+  to:
+    type: file
+    name: file2

examples/graph3b.yaml

@@ -0,0 +1,44 @@
+---
+graph: mygraph
+types:
+  noop:
+  - name: noop1
+  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
+  - name: '@@file3'
+    path: /tmp/mgmt/f3
+    content: |
+      i am f3, exported from host B
+    state: exists
+  - name: '@@file4'
+    path: /tmp/mgmt/f4
+    content: |
+      i am f4, exported from host B
+    state: exists
+collect:
+- type: file
+  pattern: ''
+edges:
+- name: e1
+  from:
+    type: noop
+    name: noop1
+  to:
+    type: file
+    name: file1
+- name: e2
+  from:
+    type: file
+    name: file1
+  to:
+    type: file
+    name: file2

examples/graph4.yaml

@@ -0,0 +1,18 @@
+---
+graph: mygraph
+types:
+  file:
+  - name: file1
+    path: /tmp/mgmt/f1
+    content: |
+      i am f1
+    state: exists
+  - name: '@@file3'
+    path: /tmp/mgmt/f3
+    content: |
+      i am f3, exported from host A
+    state: exists
+collect:
+- type: file
+  pattern: ''
+edges:

examples/graph5.yaml

@@ -0,0 +1,13 @@
+---
+graph: mygraph
+types:
+  file:
+  - name: file1
+    path: /tmp/mgmt/f1
+    content: |
+      i am f1
+    state: exists
+collect:
+- type: file
+  pattern: ''
+edges:

examples/graph6.yaml

@@ -0,0 +1,6 @@
+---
+graph: mygraph
+types:
+  noop:
+  - name: noop1
+edges:

examples/purpleidea.service

@@ -0,0 +1,8 @@
+[Unit]
+Description=Fake service for testing
+
+[Service]
+ExecStart=/usr/bin/sleep 8h
+
+[Install]
+WantedBy=multi-user.target