toRational added
toRational exported
fixes to is{Non,}{Posi,Nega}tive;
Roughnum equals, is{Integer,Rational} all return false
added num-is-{rational,roughnum,{non-,}{posi,nega}tive}
added tests for num-is-...;
use is%(within(...)) to test results of roughnum calculations
Roughnum.prototype.equals should (always) raise an exception
check that roughnum == raises error