Dmglib

This version comes with the following contributions by drunkbatya:

- Feature: Added ability to create blank dmg images in a variety of formats
- Feature: Added functionality to detach already attached dmgs

This version comes with the following contributions by slonopotamus:

- Feature: Adds option to explicitly specify the mount point (https://github.com/0xbf00/dmglib/pull/4)
- Bugfix: Removes a workaround from the project that resulted in errors on more recent versions of macOS (https://github.com/0xbf00/dmglib/pull/5).