update README on getting Git on Ubuntu;
update setup.sh of Ubuntu on installing Guake;
update README on getting RVM, Ruby, and Rails on Ubuntu;
update setup.sh of Ubuntu on installing Git;
update setup.sh of Ubuntu on installing Zsh;
update setup.sh of Ubuntu on installing Curl;
update setup.sh of Ubuntu on installing RVM, Ruby, and Rails;
Merge branch 'master' of https://github.com/ctrl-alt-del/devenv