Set default :pty value to false

`:pty` had previously been incorrectly set to default to `true`

Closes issue #652
Merge pull request #698 from capistrano/fix/default-pty

Set default :pty value to false
Super simple Gemspec tweak to fix #679
Merge pull request #700 from capistrano/fix/capify-executable

Super simple Gemspec tweak to fix #679
Don't do :cleanup twice

As it's already beeing called from https://github.com/capistrano/capistrano/blob/master/lib/capistrano/tasks/deploy.rake#L22
Update README.md

add missing "bring" to example sentance
Merge pull request #710 from nigelramsay/patch-1

Update README.md
Set stage at the beginning to be able to use it from config/deploy.rb
Warn developers that :all is a meta role
Fix for #705
Merge pull request #711 from kirs/role-all-warning

Warn developers that :all is a meta role
Merge pull request #712 from kirs/patch-6

Set stage before requiring config/deploy.rb
Default stage template cleanup

Since `stage` is already set (https://github.com/capistrano/capistrano/pull/712), we don't need to declare it twice here.
Merge pull request #713 from kirs/patch-7

Default stage template cleanup
Merge pull request #709 from kirs/patch-5

Don't do :cleanup twice
Merge branch 'master' into 3.1.x