Shell#ask: support a noecho option for stdin
Update Ask documentation and change API to be :echo => false
Merge remote-tracking branch 'socialcast/stdin-noecho-support'

* socialcast/stdin-noecho-support:
  Update Ask documentation and change API to be :echo => false
  Shell#ask: support a noecho option for stdin

Conflicts:
	spec/shell/basic_spec.rb
Remove and_return from negative receive assertion.
Fix table spec.