added move/rename, copy and other features

[escapecode]

Added

• move/rename files
• copy files
  working on
  • add_if_writable and setup_file_save_formats to be used with save_image_cb() find formats files can be converted to

[escapecode]

Viewnior is a great app. Small, fast and functional. I added some features that I use all of the time, but my pull request will give you warnings. Specifically, there will be warnings relating to "add_if_writable". That code I pulled from the GDK site, but something is amiss. If you want to get rid of the warnings without fixing, just remove "add_if_writable" and "setup_file_save_formats". I left those functions in because they should be an easy fix for somone with the time.

Also, I was thinking of holding off on my submission, but have to jump on other code projects at the moment. I don't know when I will get back to working on this. So it's out there for others to look at, expand upon and use.