Implement Thor

- Remove old sapling.rb file
- Add new directory bin/
- Add new version of sapling.rb

bin/sapling.rb

@@ -0,0 +1,45 @@
+#!/usr/bin/env ruby
+
+require 'thor'
+require 'yaml'
+
+Dir[File.join(__dir__, 'lib', '*.rb')].each { |file| require file }
+
+# The main Sapling interface.
+class Sapling < Thor
+  desc 'read TREE', 'Load and traverse the TREE'
+  def read(tree)
+    exit if verify_tree(tree)
+    puts 'Welcome to Sapling, a Dialogue Tree Utility.'
+    speaker = Dialogue::Speaker.new(YAML.load_file(tree), false)
+    speaker.conversation
+  end
+
+  desc 'edit TREE', 'Edit a new or existing TREE'
+  def edit(tree = '')
+    puts 'Welcome to Sapling, a Dialogue Tree Utility.'
+    if !tree.empty?
+      puts "Loading tree: #{tree}"
+      exit if verify_tree(tree)
+      gardner = Planter::Spade.new(YAML.load_file(tree, false))
+    else
+      puts 'Creating a new tree!'
+      gardner = Planter::Spade.new(SKELETON_TREE)
+    end
+    gardner.plant
+  end
+
+  desc 'serve TREE', 'Load TREE in a web-based interface'
+  def serve(tree)
+    exit if verify_tree(tree)
+    puts 'Sinatra will be cool.'
+  end
+
+  desc 'export TREE', 'Save a portable HTML version of TREE'
+  def export(tree)
+    exit if verify_tree(tree)
+    puts 'Cool feature, bro!'
+  end
+end
+
+Sapling.start(ARGV)