`hps init` failing if not run in clean directory

[rossgray]

Just a small idea for improvement: from the usage instructions it was not clear to me that hps init needs to be ran in a new directory:

First, initialize a new HugoPhotoSwipe directory with: hps init

This sounds like the hps init command will initialize the new directory for me. So when I ran hps init in an existing Hugo repo the command failed.

Perhaps it would be a good idea for the init script to check if it is being ran in a clean directory and if not, return an error to the user?

[GjjvdBurg]

Thanks for checking out HugoPhotoSwipe! I've updated the instructions and added support for skipping non-album directories in version 0.0.9.