Importing a stack of maps: timeinput

With more timesteps, use basename of filename for timestep numbers

Basename is always 8 positions, extension 3 positions, for instance with 10000 timesteps:

RF000000.001  RF000000.002  RF000000.003  RF000000.004  RF000000.005  RF000000.006
....
....
....
RF000009.995  RF000009.996  RF000009.997  RF000009.998  RF000009.999  RF000010.000