Get Files from File input line to match user expectation

- If a user manually edits the input file lines, clicking start should
  use that. Currently it just looks at the files selected last via file
  browser
- We want to allow users to manually enter file paths in field. Which
  is why the field hasn't been set to read-only

src/interface/desktop/file_browser.py

@@ -65,4 +65,7 @@ class FileBrowser(QtWidgets.QWidget):
             self.lineEdit.setText(",".join(self.filepaths))    
 
     def getPaths(self):
-        return self.filepaths
+        if self.lineEdit.text() == '':
+            return []
+        else:
+            return self.lineEdit.text().split(',')