#5 Import data in fixed-width format.

[Bo Peng]

This is a patch to allow our importer to import data with fixed-with input. The starting columns are specified as 1,4,10,25 etc as the delimiter in the description of the format. The delimiter will be read as a tuple, which will be used to read data from input file.

I am not sure if this is really that usable (because in our case the width of columns of "vtools output" will change with width of data.