CGE2: Make some static functions non-static.

EncryptedStream -> CGE2Engine
Namely:
* CGE2Engine::number(char *s)
* char *CGE2Engine::token(char *s)
* int CGE2Engine::takeEnum(const char **tab, const char *text)
* ID CGE2Engine::ident(const char *s)
* bool CGE2Engine::testBool(char *s)
* int CommandHandler::com(const char *com)