Fix a bug where -1 was parsing as 1

Hello @dpup, 

Please review the following commits I made in branch 'nick-numbers'.

f3cf9d05e63e5286cc6e7f4722ef7ec70ff846a6 (2014-01-08 12:18:36 -0800)
Fix a bug where -1 was parsing as 1

R=@dpup