remove httparty and addressable runtime dependecies and add json

Author: Deepak

open_weather.gemspec

@@ -14,7 +14,5 @@ Gem::Specification.new do |gem|
   gem.executables          = gem.files.grep(/^bin/).map{ |f| File.basename(f) }
   gem.require_paths        = ["lib"]
   gem.add_development_dependency "rspec"
-
-  gem.add_runtime_dependency 'httparty'
-  gem.add_runtime_dependency 'addressable'
+  gem.add_runtime_dependency 'json'
 end