remove rails/duplicable and related methods (#614)

Author: KazuCocoa

lib/appium_lib.rb

@@ -3,7 +3,6 @@
 Encoding.default_internal = Encoding::UTF_8
 
 require 'forwardable' unless defined? Forwardable
-require_relative 'appium_lib/rails/duplicable'
 
 # Init global driver
 $driver = nil

lib/appium_lib/driver.rb

@@ -439,7 +439,7 @@ def initialize(opts = {})
 
     # Returns a hash of the driver attributes
     def driver_attributes
-      attributes = {
+      {
           caps:             @caps,
           automation_name:  @automation_name,
           custom_url:       @custom_url,
@@ -455,12 +455,6 @@ def driver_attributes
           wait_timeout:     @appium_wait_timeout,
           wait_interval:    @appium_wait_interval
       }
-
-      # Return duplicates so attributes are immutable
-      attributes.each do |key, value|
-        attributes[key] = value.duplicable? ? value.dup : value
-      end
-      attributes
     end
 
     def device_is_android?