Returns true if there is a system property with the supplied name
 whose value matches the expected value. The 
 and  parameters are required, and the parameter
 value supplied is the expected system property value, ignoring case.
 
 This rule takes an optional parameter 
 which, if true, will test whether the value of the system property
 contains, ignoring case, the supplied property value, rather
 than matching the entire string. Boolean.valueOf(String) is
 used to determine whether the value supplied to  
 is true or false.