work from week4's class
add week5
Merge branch 'master' of https://github.com/UWE-Ruby/RubyFall2013
the mid-term
Merge branch 'master' of https://github.com/UWE-Ruby/RubyFall2013
add week 6 materials
some more week 6 materials
small change to slides
Merge branch 'master' of https://github.com/UWE-Ruby/RubyFall2013