Allow creation of tags with filament color alpha channel value

[raihei]

Sorry, messed up my fork and had to create a new pull request.

• Enhancement Request: Pass alpha channel in RGB code to allow for transparent filaments #20
• Commented out some script execution which seemed to lead to warnings "script preview_rfid_data already running" in some cases and seemed to be not needed.

Still don't know, what you meant with that comment: #40 (comment)

[spuder]

This looks good. I have not had a chance to test it yet. Is this working on real hardware?

[raihei]

Sure