Make the structure of the ESC/POS commands less opaque

(The commands are intended to be readable by people who grew up with ANSI
 escape codes so represent them that way in the code)
Actually use the barcode height and width parameters

(And reverse their order in the method signature so corrections to the
range checks don't break existing code)
Make BarcodeSizeError and BarcodeTypeError display the erroneous value

(MUCH more helpful for debugging)
Accept "CODABAR" as an alias for "NW7" in barcode()
Add the setup.py-produced "build" folder to .gitignore
Allow bypassing the resizing and height-cropping steps in fullimage()
Apply the cash drawer fix detailed in Issue 10 on the Google Code repo.

https://code.google.com/p/python-escpos/issues/detail?id=10
Ensure QR codes have a border large enough for successful scan

(The QR code spec requires a border at least 4*box_size thick but we can't
 just set border=16 because that results in a QR code more than 255px tall
 and I'm not yet ready to use fullimage() as a backend for it)
Allow bandsize to be varied in fullimage()
Start on a command-line interface to the library (still hard-codes USB ID)

(...and still needs better documentation)
Adjusted QR error correction

Maxed out the error correction on QR code generation for vastly improved recognition. The trade-off is that the amount of bytes that can be stored are reduced.
Merge pull request #2 from inversesandwich/patch-1

Many fixes :)