Keep the record of last folder and settings when importing/exporting data

If we have to repeat several time the same operation of importing/exporting: a block, the survey data or the photo positions, ContextCapture will always get to the same windows location (i.e. the project folder) and reset to the default settings. It would be useful to keep the last windows location and the last import/export settings so the user could save a lot of time when he has to repeat the same operation several times