Make largeint() generate integers

Previously it generated floats.

In shrinking function, since Val is a proper integer, instead of checking for <
1 or > 1 then do the same operation (`Val / 10`), reverse the logic and
special-case 0 instead. It should read as "if it is 0 we are done shrinking,
otherwise we should / 10".

Fixes #67
2 files changed