Create _drafts folder if it does not exist

- When using the drafts command, if the _drafts folder does not already exist, create it. This prevents errors when running the draft command for the first time on Jekyll 2.5.3.

Author: campo

lib/jekyll-compose/version.rb

@@ -1,5 +1,5 @@
 module Jekyll
   module Compose
-    VERSION = "0.2.0"
+    VERSION = "0.2.1"
   end
 end

lib/jekyll/commands/draft.rb

@@ -19,6 +19,8 @@ def self.init_with_program(prog)
       def self.process(args = [], options = {})
         raise ArgumentError.new('You must specify a name.') if args.empty?
 
+        Dir.mkdir("_drafts") unless Dir.exist?("_drafts")
+
         type = options["type"] || Jekyll::Compose::DEFAULT_TYPE
         layout = options["layout"] || Jekyll::Compose::DEFAULT_LAYOUT