add new method qrcode_decode

[hanpeic]

updated jar file version
improve QR code decode ability same as the website: zxing.org

[ecin]

Thanks for your PR! Will review shortly. 😄

[ecin]

@hanpeic can you add a description that explains how this code works, and why it's needed?

By the way, thanks for adding so many fixtures to the code!

[hanpeic]

Hi @ecin thanks for your quick reply. When I call this gem to parse QR code, I find some QR code parse failed, but if I upload to zxing.org, it could get the result. After I checked the source code of zxing.org, the key point is this line:
https://github.com/zxing/zxing/blob/master/zxingorg/src/main/java/com/google/zxing/web/DecodeServlet.java#L367

It tries 'HybridBinarizer' to parse again if first time failed. so I add same code in this gem. to make sure if a QR code could parse by zxing.org, then It could parse by this gem too.