pyILPER 1.7.0 beta release

[rprosperi]

Suggested small changes for the PRINTER device tab:

1. Add the color scheme of 'Black on White' (I guess called Black in the menu), so it looks like real printer output.

2. When turning-off log buffering, open a Save as... dialog to allow user to save what they just collected to a text file wherever they choose, rather than needing to go hunt through folders to find the 'home' folder for pyLIPer to locate the printer log. I would also keep the file in the home folder as expected even if also saved elsewhere. Canceling the Save-as dialog also keeps the log file in the home folder.

And btw, what is the pyILPer home folder for the BETA configuration?