Convert balanced ternary strings to/from signed integers
Usage:
var bts2n = require('balanced-ternary').bts2n;
var n2bts = require('balanced-ternary').n2bts;
bts2n('10i'); // 8
n2bts(8); // '10i'
bts2n(s) converts from balanced ternary string to signed integer, n2bts(n) converts from signed integer to balanced ternary string.
Digits 1, 0, and i correspond to +1, 0, and -1.
Reference: Balanced ternary on Wikipedia