Update for gemfile windows support

* Exclude gems that don't work on windows (kgio, dalli, gctools)
* Add new gems necessary on windows (memcache-client as dalli
replacement, tzinfo-data)
* Update gems where the old version couldn't be installed on windows but
the new version can (nokogiri, pg, bcrypt)

I don't think this should break anything on non-windows platforms since
the additions/removals only take effect on windows, and the version
updates don't appear to have changed anything huge.

Gemfile

@@ -21,8 +21,10 @@ gem "pry", :group => [:test, :development]
 gem "byebug", :group => [:test, :development]
 gem "rails", "~> 4.1.8"
 gem "pg"
-gem "kgio"
-gem "dalli"
+gem "kgio", :platforms => :ruby
+gem "dalli", :platforms => :ruby
+gem "memcache-client", :platforms => [:mswin, :mingw, :x64_mingw]
+gem "tzinfo-data", :platforms => [:mswin, :mingw, :x64_mingw]
 gem "delayed_job"
 gem "delayed_job_active_record"
 gem "simple_form"
@@ -58,7 +60,7 @@ gem 'aws-s3', :require => "aws/s3", :git => "https://github.com/fnando/aws-s3.gi
 group :production do
   gem 'unicorn', :platforms => :ruby
   # gem 'unicorn-worker-killer'
-  gem 'gctools'
+  gem 'gctools', :platforms => :ruby
   gem 'capistrano-unicorn', :require => false
 end