VirtueMartModelState::getStates and VirtueMartModelCountry::getCountries changes the internal cache ->_data, but does NOT modify ->_id...
The proper fix would be in VM's model classes to set the id to -1.

However, as a workaround we can call setId twice to ensure the cache is always invalidated and getData returns the proper object

Version 4.0.1: Handle = and html in the basic plugin's rule names; hide the quotes around rule names in the basic plugin; fix typo in the operator regexp

Version 4.0: Fix globals warning; Add Values_Debug variable; Add contains_any/contains_all functions

V3.96: Apply bugfixes in the setCartPrices function (from the VM repo), which I had to copy from vmpsplugin.php

-) Implement custom definitions (Variable or Definition as keyword) of the form:
    Variable|Definition=VARNAME; [Value=]SOMECOMPLEXVALUE
-) Such defined variables can be used in all further rules.
-) Add "Condition=" keyword to indicate that a certain value is a condition (e.g. a variable defined as implemented here).
   This is needed to distinguish single-variable (or function-call) conditions from shipping costs, where the "Shipping=" was left out.
   Previously, only terms that contained a comparison operator were detected to be conditions. This excluded conditions like
   "issubset(...)" or "MyZIPConditions" (i.e. functions returning boolean values and boolean values stored in variables).
-) The rule-matching code was moved to its own function, so the logic to distinguish variable definitions and (later on) modifiers
   is in only one place.

Special care is taken (using a global array of messages...) to ensure that the message is not printed twice...

Internally, operators are converted to UPPER case, while function names are converted to lower case.