Add a statSync to get the file mtime and set LastModified

[stujo]

#37 Attempting To Address

[MathieuLoutre]

Great solution. Thanks for this and sorry it took so long to review and merge this.

[AllanHodkinson]

Hi,
Pretty sure there is a bug in this code for the getObject function:
If the requested file doesn't exist then
var stat = fs.statSync(path);
will throw an untrapped error.
The fix is to move this line into the if (!err) statement.

I can do you a fix if you like but it's probably quicker to do it yourselves.
Thanks,
Allan

[MathieuLoutre]

Thanks Allan, not sure how I missed that but good spot! The fix should be in and published in 2.5.1 if I didn't mess anything up this time :)