ConvertRating

A template for converting a rating, as printed in a magazine into:

• something nice to display
• a value out of 100 for use in Sega Retro averages

(haven't worked out how best to do this - whether this needs to be aware of magazine pages, or if magazine pages need to be aware of this)

Systems to support:

• 0-4 stars
• 1-4 stars
• 0-5 stars
• 1-5 stars
• 0-10 stars
• 1-10 stars
• 0-4 (numbers)
• 1-4 (numbers)
• 0-5 (numbers)
• 1-5 (numbers)
• 0-10 (numbers)
• 1-10 (numbers)
• 0-20 (numbers)
• 1-20 (numbers)
• 0-100 (percentage)
• 0-1000 (ACE)
• A-F

multiple instances of the above (e.g. support "1,2,3,4" for EGM)

added text. e.g. later issues of the UK Official Dreamcast magazine, 7 = "good".

it should be able to detect if a given value is invalid. Some magazines could be using multiple systems depending on context.

The user should not be expected to calculate anything.