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!

test/test-yamlfmt.sh

@@ -37,7 +37,7 @@ find_files() {
 
 bad_files=$(
 	for i in $(find_files); do
-		if ! diff -q <( ruby -e "require 'yaml'; puts YAML.load_file('$i').to_yaml" 2>/dev/null ) <( cat "$i" ) &>/dev/null; then
+		if ! diff -q <( ruby -e "require 'yaml'; puts YAML.load_file('$i').to_yaml.each_line.map(&:rstrip).join(10.chr)+10.chr" 2>/dev/null ) <( cat "$i" ) &>/dev/null; then
 			echo "$i"
 		fi
 	done