Allow more button / keyboard options for media capturing

[jueank]

Currently, only a subset of the usual cabinet buttons / keyboard codes can be used for triggering media capture. Some of the button combinations cannot be used on certain tables, because these buttons are being used by the table script. Example: magnasave buttons. Depending on the script code, the keyboard/button codes are consumed by the script and not 'forwarded' to other applications. Another example for magnasave: switching LUTs. There are still a lot of tables using magnasave for that.
It would be nice to use more button / keyboard combinations like Extra ball (or the corresponding keyboard code).