Fix/improve the SSL configuration

- Do not extend config.express.serverOptions with config.ssl before
  the config validation is done: the former is undefined by default
  (#843) and that's OK as it would fire a validation warning otherwise.

- Use _.merge instead of the undefined _.recursive.defaults to set the
  default values of config.express.serverOptions (#844). Use _.extend
  if the serverOptions wasn't defined by the user's config.
Merge pull request #845 from wolneykien/master

Fix/improve the SSL configuration
Merge branch 'master' of github.com:balderdashy/sails into development
Imposed harsher restriction about trying to lift sails in a directory without a fritndly-looking package.json file. Refactored and added some comments.
Rebased 201:created part of #773 (3d086c731e6492e0efe983fa4033cf9528f21bcb)