Compatibility

Hello

This is a set of two fixes to make the deploy tasks work when a user has a non sh compatible shell (e.g. korn, fish)

The gist of it is to explicitly execute all remote commands in the sh shell, and change the escaping of the executed command to avoid compatibility problems.

I couldn't test these changes without also fixing two issues, please tell me if I should put them in different pull requests for clarity:
- allow to call the AbstrackTask#runCommandRemote without changing directory first (when the directory doesn't exists yet, it makes the deploy crash)
- I added the option to specify a directory owner in the deployment configuration file, to allow to skip the directory ownership guess work altogether or specify a different user:group than the one used for the deployment.

This is my first commit on this project, please telle me if you need changes on the formatting for instance or really anything else.