Issue 1a

[serratus]

This pull request primarily solves issue #1 alongside other minor updates listed below:

Features

• Added support for web-worker (using 4 workers as default, can be changed through config.numOfWorkers)
• Due to the way how web-workers are created, the name of the script file (config.scriptName) should be kept in sync with your actual filename
• Removed canvas-overlay for decoding (boxes & scanline) which can now be easily implemented using the existing API (see example)

API Changes

In the course of implementing web-workers some breaking changes were introduced to the API.

• The Quagga.init function no longer receives the callback as part of the config but rather as a second argument: Quagga.init(config, cb)
• The callback to Quagga.onDetected now receives an object containing much more information in addition to the decoded code.
• Added Quagga.onProcessed(callback) which provides a way to get information for each image processed.
  The callback receives the same data object as Quagga.onDetected does. Depending on the success of the process the data object
  might not contain any resultCode and/or box properties.

[WebHunters]

What time to support the two-dimensional code scanner

[serratus]

@WebHunters please post your comments related to 2-D codes to the already existing issue #2. Currently, the implementation of 2D barcodes has not even started yet. Most of my work, especially the localization of barcodes, can only be applied to 1D codes. What kind of 2D barcodes do you consider? QR codes? Please post your question/answer to #2. Thanks