The biggest change however will be the inclusion of a double-resolution Retina display. Like when the iPhone and iPad got the Retina upgrades, the MBP interface will still look the same, only smoother and crisper. Apps that use text or vector drawing will immediately see the benefits, and it'll be light work to update UI elements to have 2x versions. Apps that want to take deeper advantage of the extra pixels (like all of Adobe's Creative Suite) will need a bit more work, though I wouldn't be surprised if they got early access and show stuff off at WWDC as an example.
The appendix is presented as a complete history of the Compson family lineage, beginning with the arrival of their ancestor Quentin Maclachlan in America in 1779 and continuing through 1945, including events that transpired after the novel (which takes place in 1928). In particular, the appendix reveals that Caroline Compson died in 1933, upon which Jason had Benjy committed to the state asylum, fired the black servants, sold the last of the Compson land, and moved into an apartment above his farming supply store. It is also revealed that Jason had himself declared Benjy's legal guardian many years ago, without their mother's knowledge, and used this status to have Benjy castrated.