Remove .bat file.

Composer is supposed to deal with this automatically.
Merge pull request #169 from platformsh/remove-bat-file

Remove .bat file.
Validate the SSH public key file before attempting to add it.
Fix wrong confirm delete action in drush-aliases command.
Merge pull request #174 from pjcdawkins/validate-ssh-key

Validate the SSH public key file
Make toolstack detection error less scary - addresses #173
Merge branch 'development'
Release v1.4.3