#72 Browse feature for WorldMaker plugin

[Rick Tanner]

In the WorldMaker plugin dialog, having the option available to browse for a "Location" directory instead of manually entering the file path to the map files used to generate the final image.

Also, a browse option for the "PictureDirectory" and "WorldPicture" location. Perhaps, have those fields autofill based on the source directory choses in "Location" ?

Hopefully this would make the plugin more easier or friendly to use