country metadata sub-options are not working

[jpazvd]

the suboptions of the countrymetadata when called from wbopendata are not working.

_countrymetadata, match(countrycode) incomelevel _countrymetadata, match(countrycode) region

and

wbopendata, match(countrycode) incomelevel wbopendata, match(countrycode) region

are not equivalent

[ckrf]

I made a pull request that fixes the suboptions: https://github.com/jpazvd/wbopendata/pull/41

With respect to the equivalence between wbopendata, match(countrycode) incomelevel (should this be (income?) wbopendata, match(countrycode) region (should this be regions?) I'm not sure what exactly is the desired behavior.