Remember most recent directory for texture export
When creating a new project and adding an .fbx file, the Open dialog starts in the most recent directory where an .fbx file was loaded from. (Which is very convenient, and greatly appreciated!)
Likewise, when saving the project as an .spp file, the Save dialog starts in the most recent directory where a project was saved. (Similarly convenient!)
However, when exporting textures, it always defaults to the user's "Documents/Allegorithmic/Substance Painter/export" directory, regardless of where textures were last exported to... which is a lot less convenient.