rOpenGov/iotables: Simpler interface, new vignette, cross-checked against published results.

This is a much improved version with highly improved performance, more consistent function interface and far more readable code. The last CRAN release is stable, the following version will be a stable, better release candidate.

New vignette United Kingdom Input-Output Analytical Tables to compare analytical function results with published results from the UK National Office for Statistics.

The package website has already three long vignettes.