Deprecated numpy types

[settwi]

As of numpy 1.20 np.float and np.int are deprecated; in the past they were just aliases.

So those should be removed from the code (main code + tests)

via (e.g.):

grep -rl 'np.int' . | xargs sed -i 's/np.int/int/g'
grep -rl 'np.float' . | xargs sed -i 's/np.float/float/g'