Adding some options into the Googlechart engine and fixing a small bug.

Hello,

I modified the qr_code_google_chart.module to expose more settings.
You can find the settings list on the API here: http://code.google.com/apis/chart/docs/gallery/qr_codes.html

I've also corrected a small bug in the qr_codes_theme() function in qr_codes.module. There were 2 missing arguments: Alt and Title.