Global y1

I BELIEVE y1 is being created globally in the crop function, and that x2 is not actually being used. So, I've changed local x1, x2 to local x1, y1. #177

Author: bnsh

init.lua

@@ -470,7 +470,7 @@ local function crop(...)
  else
  iwidth,iheight = src:size(2),src:size(1)
  end
- local x1, x2
+ local x1, y1
  if format == 'c' then
  x1, y1 = math.floor((iwidth-width)/2), math.floor((iheight-height)/2)
  elseif format == 'tl' then