Created the base Writer object for all barcode encoding, then wrote a QR Code version...

Created the base Writer object for all barcode encoding, then wrote a QR Code version. A Writer encodes a series of raw bytes into a 2D greyscale bitmap, represented by a ByteArray. This seems like a better container than MonochromeBitmapSource, because we may want shades of grey when encoding future formats. The next step is to hook this up to the Android client.

git-svn-id: http://zxing.googlecode.com/svn/trunk@716 59b500cc-1b3d-0410-9834-0bbf25fbcc57