New properties: system.version_num and system.version_hex, initialized with

the values of the newly defined macros of the same names. These allow easy
comparison for scripts. Example:
    if(system.version_num < 31301) /* v3.13b */
        print("version 3.13b or later required");
system.version_hex allows easy major/minor version number checking, parsing
or printing using right-shift operations instead of division/rounding. Example:
    31301/100 == 313.01
    0x31301>>8 == 0x313