More Magic

Quite a few of the attributes of classes in the cache are represented as both strings and numeric values simultaneously: for example the CompType attribute of AptPkg::Cache::Depends objects evaluates as a string to something like ">=", and as a number as a constant AptPkg::Dep::GreaterEq in this case).

The rationale is that strings are convienient to output, but numbers are faster to compare, and additionally allow the storage of extra information (such as AptPkg::Dep::Or for CompType).

These constants are defined by the AptPkg module.