cd(dir, options = {})
  
	Class Public methods
	Options: verbose
Changes the current directory to the directory dir.
If this method is called with block, resumes to the old working directory
after the block execution finished.
FileUtils.cd('/', :verbose => true)   # chdir and report it
FileUtils.cd('/') do  # chdir
  [...]               # do something
end                   # return to original directory
chdir