atomic-maybe-uninit

• Support ARMv6-M. (#4)

• Optimize AArch64 128-bit atomic load/store when the lse2 target feature is enabled at compile-time.

• Implement MIPS32r2 32-bit swap.

• Implement MIPS64r2 32-bit and 64-bit swap.

• Support MIPS32r2 and MIPS64r2.

• Add #[must_use] to constructors.

• Support ARMv7-A, ARMv7-R, ARMv7-M, and ARMv8-M.

• Optimize aarch64 atomic swap when the lse target feature is enabled at compile-time.

• Document safety requirements of functions in raw module.

• Support AArch64.

• Support X32 ABI.

• Remove raw feature and always expose raw module.

Initial release