v0.3.4

* Update `comb.string.format` to handle signing numbers with padding properly
  * `comb.string.format('%+07.2d', 10); //"+010.00"`
  * `comb.string.format('%+07.2d', -10); //"-010.00"`
  * `comb.string.format('%+ 7.2d', 10); //" +10.00"`
  * `comb.string.format('%+ 7.2d', -10); //" -10.00"`