added nice syntax errors

lib/coffee_script/parse_error.rb

@@ -0,0 +1,19 @@
+module CoffeeScript
+
+  class ParseError < Racc::ParseError
+
+    def initialize(token_id, value, stack)
+      @token_id, @value, @stack = token_id, value, stack
+    end
+
+    def message(source_file=nil)
+      line      = @value.respond_to?(:line) ? @value.line : "END"
+      line_part = source_file ? "#{source_file}:#{line}:" : "line #{line}:"
+      id_part   = @token_id != @value.inspect ? ", unexpected #{@token_id.downcase}" : ""
+      "#{line_part} syntax error for '#{@value.to_s}'#{id_part}"
+    end
+    alias_method :inspect, :message
+
+  end
+
+end