CORE: When using uncommon iNes 1.0 features, issue a warning

[zeta0134]

For broad compatibility, we try to support anything the header requests within reason. However, for iNes 1.0 in particular, support for anything meaningful in bytes 7-15 is rather uncommon, and the bytes were occasionally filled with garbage data by various software creation utilities.

As our project gains debugging features and becomes a more useful target for developing new software, we should detect uses of these uncommonly-supported features and issue a warning to new homebrew authors.