Remodelling Observers/Examples that rely on UB, API cleanups (#950)
* Tackling UB
* PtrMut -> MutPtr, moved mapobservers to non-UB
* QEMU fixes
* test fixes
* qemu
* Change all interfaces, fix all fuzzers
* fixes
* fix more fixes
* fmt
* fix qemu sugar
* fix some qemus
* atheris
* fmt
* more fmt
* most fmt
* more fix
* nyx fyx
* fix qemu
* clippy, fixes
* more fixes
* no unfix, only fix
* fix
* fix
* more clippy
* fixes
* ListObserver
* fmt, clippy
* fix qemu on arm
* update zlib target
* fix?
* fix
* added migration guide
* ignore doc
* fix symcc
* fix new win fuzzer
* Fixes, rename PTR_SIZE to PTR_NUM
* Try fix linking on win
* Trying to fix win linking
* more cov
* trying to fix win some more
* trying to fix mac
* trying to fix mac
* Fix tests
* Fix tests
* trying to fix win
* more mac
* giving up for windows
* fmt
* python3
* mac?
* undo windows tests
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