t.remove change rf flags

[lucadelu]

t.remove right now remove both temporal dataset and raster maps with -rf flags.

I suggest to change in this way:

• d: Remove temporal dataset
• r: Remove only raster maps
• f: Force removal (required for actual deletion of files)

what do you think?

[veroandreo]

Desired behaviour could be:

• no flag: shows warning that -f should be used to force removal
• only -r: shows maps in the stds that will be removed and warns that also -f should be used to remove the maps
• only -f: removes the stds
• -rf: removes stds and maps from the temporal framework
• -d: complete clean-up (removes stds and maps from temporal framework and from mapset)