Explicitly require ActiveSupport's Hash#except

This allows Grape to be run with ActiveSupport 3, without Rails.
In ActiveSupport 4, this file ended up being required as a
dependency of `active_support/core_ext/object/conversions`. Also,
Rails itself includes this file.

Author: wagenet

CHANGELOG.md

@@ -17,6 +17,7 @@ Next Release
 * [#1045](https://github.com/intridea/grape/pull/1045): Do not convert `Rack::Response` to `Rack::Response` in middleware - [@dmitry](https://github.com/dmitry).
 * [#1048](https://github.com/intridea/grape/pull/1048): Only dup `InheritableValues`, remove support for `deep_dup` - [@toddmazierski](https://github.com/toddmazierski/)
 * [#1052](https://github.com/intridea/grape/pull/1052): Reset `description[:params]` when resetting validations - [@marshall-lee](https://github.com/marshall-lee).
+* [#1088](https://github.com/ruby-grape/grape/pull/1088): Support ActiveSupport 3.x by explicitly requiring Hash#except - [@wagenet](https://github.com/wagenet)
 
 0.12.0 (6/18/2015)
 ==================

lib/grape.rb

@@ -13,6 +13,7 @@
 require 'active_support/core_ext/object/conversions'
 require 'active_support/core_ext/array/extract_options'
 require 'active_support/core_ext/hash/deep_merge'
+require 'active_support/core_ext/hash/except'
 require 'active_support/dependencies/autoload'
 require 'multi_json'
 require 'multi_xml'