v1.6: Fixed to handle new certificate names and Xcode pathes + added recursive codesigning

- FIX: Fixed certificate detection mechanism to cater for new
certificate names
- FIX: Fixed invalid codesign_allocate path that prevented codesign
command to function
- NEW: Recursive codesigning of plugins inside the app bundle. This is
necessary for dynamic libraries but will also remove warnings for
bundles upon submission to the App Store