Miscellaneous memory leak fixes
Created by: arandomhuman
The changes in wlroot include a very minor leak in x11/backend.c (7bc26579) and a bug in tablet_manager_v2 (9f511ae9).
The other commits to the examples include setting keymaps more securely (7105864e), and removing pointers in multi-pointer (6af77e3d).
Please let me know if some commits are better merged squashed (say, all the edits to examples).