refined fxml (nicer TableView appearance)

TableColumns now have prefWidth="100.0"
fxml: id's for TimeTable view columns

...this way CellValueFactory etc are able to recognize the column (I
hope)
(still a mess)

idea: extend TableCell to create a custom TableCell that allows
displaying multiple 'overlapping' activities in the same cell

in other words, a cell that contains hbox/vbox/gridpane/something
updated comments
Updated progress diary

Retroactively updated work hours (based on git logs)