Replacing process.nextTick with setImmediate

This will solve Maximum call stack size exceeded error when dealing with large files.

When reading a large file with many lines, the maximum call stack size exceeded error occur. I was trying something like the following:

lineReader.eachLine('file.txt', function(line, last) {
...

}

(node) warning: Recursive process.nextTick detected. This will break in the next version of node. Please use setImmediate for recursive deferral.

RangeError: Maximum call stack size exceeded