Adding a basic custom config file

* Also adding in a logger
* Added a sample for custom config
* Saving a png now creates _output

samples/custom-config.rb

@@ -0,0 +1,6 @@
+#!/usr/bin/env ruby
+require 'squib'
+
+Squib::Deck.new(config: 'custom-config.yml') do
+	
+end

samples/custom-config.yml

@@ -0,0 +1 @@
+dpi: 300