Map making support and conversion tool: post-Atlas

[Grautvornix]

Here is the latest version post-Atlas 1.13.0. The main thing is a button that was asked for while testing 1.12.0: after you convert a map, you can now open the converted copy in the target game's Atlas without leaving post-Atlas - to fix there what post-Atlas cannot, and to save - and post-Atlas follows it until it comes back. 

There is also a more detailed preview of findings in 2D and 3D.

Hope this tool can be useful when mapping or converting older maps!

CHANGELOG.md post-atlas-1.13.0.zip