rename files #4
show error message if RUBY_PLATFORM not matches Linux or Mac
move platform load code into skype.rb
add Skype::Chat and Skype::Chat::Message  #4
add Skype::Chat#post  #4
Skype::Chat#members  #4
Skype::Chat#topic  #4
cache Skype::Chat::Message object on memory #4
sort Skype::Chat#messages  #4
fix sample chat  #4
update README #4
update README
update README