Fallback to SRC files without postfix

[szapp]

Recent changes require a "_G1" or "_G2" postfix to all SRC and animation files to indicate their affiliation. This is useful for creating unified patches. However, for larger projects this results in a lot of duplicate/identical files, if the SRC/animation files do not differ between both games.

An improvement would be to fallback to SRC and animation files without neither postfix that are parsed only if no matching postfixed file is found previously. An exception should be the content ninja to ensure compatibility at all times.