select(0, 0) has different behavior than select(1, 0)

[wasade]

Probably still lingering 0-index use, where for select(1, 0), it really should actually be the root node, so a return of 0 is valid and in the case of select(0, 0), it should be the first closing parenthesis encountered, or the first tip in the tree. However, right now it returns either 0 or -1 (depending on implementation tested, which is wrong and thus requiring the use of select(0, 1) to refer to k=1. Basically, the semantics of select(0) and select(1) differ in that the former is k >= 1 and latter is k >= 0