two new classes introduced to manage data associated with mime types.
two new classes introduced to manage data associated with mime types.

TfpgMimeDataBase is a base class for data associated with mime types.
TfpgMimeDataStruct is a simple data class. Currently I'm not sure if
Variants are the way to go for storing data, so this might change in the
future.

wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI