Add tests and add a new simplified method to parse data

There is a new method to parse a file (or a buffer)

var mapper = require('node-exif');

mapper("/path/to/image.jpg", function (error, exifData, path) {

    console.log({
        path: path,
        exifData: exifData
    });
});

Quick fix

Fix #51

New node-exif parser configuration

Hello everyone,

For this version, I have added lot of new options:

• tiffOffsets (boolean) an object named "offsets" is added to exifData and contains lot of offsets needed to get thumbnail and other things.
  • fixThumbnailOffset: correct the thumbnail offset in order to have an offset from the start of the buffer/file.
  • maxEntries: Specifies the maximum entries to be parsed (setted to 128 by default)
  • ifd0MaxEntries:
  • ifd1MaxEntries
  • maxGpsEntries
  • maxInteroperabilityEntries
  • agfaMaxEntries
  • epsonMaxEntries
  • fujifilmMaxEntries
  • olympusMaxEntries
  • panasonicMaxEntries
  • sanyoMaxEntries
  • noPadding (ignore padding tag, true by default)

I have added debug() dependency, so don't forget to make a npm update.
If you want to enable exif logs, set the environnement variable "DEBUG" to "exif" before launching node.