Transfer QVD field types to resulting DataFrame

[serjko]

Hi there - loving this library, so handy for reading QVD files outside of the Qlik environment.

What would be great is to transfer the field types defined in QVD to the resulting DataFrame. So that numeric columns come over as ints/floats, dates/timestamps - as dates/times, etc. Nothing fancy but a simple mapping between QVD and Pandas data types would be very helpful in working with the resulting data frames.