This code for parsing needed to be changed because of large file handling. XmlTextReader ended up being the best solution that doesn't crash at 500 MB in. A side effect of this change is that the code for processing a given DAT is very minimal now. The entire sub-block for SL-specific DAT info doesn't need to exist anymore. Small-scale tests have given 1:1 results with previous versions but further testing is needed for large files to make sure no data is lost.
This is currently borken for reasons that I don't 100% understand. It needs to be tested further with a basic DAT to see why it doesn't seem to get every ROM.
Basically, this will output the information that's in each DAT but not in the merged and also the data that's only in every DAT. This needs testing, but it's a good start.
