[REVERTED] Categories: now with better categorising

THIS RELEASE HAS BEEN REVERTED due to not really working properly.
The below information is kept for historical reasons. Please do not use this release

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You can finally have multiple category_rules for categories, using the familiar FLEX/STRICT modes.

strict (the default) requires all the below to be true:

{
  "category_rules": {
    "type": {"rules":[["=","DD"]]}, 
    "creditAmount": { "rules": [[">",500]]}
   }
}

FLEX will be type='DD' OR 'creditAmount' > 500

{
  "category_rules": {
    "type": {"rules":[["=","DD"]]}, 
    "creditAmount": { "rules": [[">",500]]},
    "mode": "FLEX"
   }
}