Annual ChangeLog rotation.
bug #39783: add CRC definitions and update PR definitions for xmega 64/128/192 and 256 d3 devices
add bug #39783 fix
bug #41519: update SPM_PAGESIZE to 64 for tiny48 and 88
bug #40595: update high fuse byte definitions for tiny2313a and tiny4313
Add missing definitions of PCMSK0_struct registers.
bug #38516: add missing TWI and UCSR1D register and bit definitions
bug #35971, #36053: add missing register and bit definitions, update interrupt vector name for attiny2313a/ 4313.
bug #35948: remove timer2 related definitions from iom32u4.h as ATmega32U4 does not have Timer 2
Update register and bit definitions for tiny 13a/24a/44a/84a, tiny167 and mega328p
bug #40567: update EECR bit definitions for tiny13a (iotn13a.h)
Add new devices AT90pwm161, ATA5272, ATA5505, ATA5790, ATA5795, ATA6285,
ATA6286, ATmega1284, ATmega128A, ATmega164PA, ATmega165PA, ATmega168PA,
ATmega3250PA, ATmega325PA, ATmega3290PA, ATmega32A, ATmega48PA, ATmega64A,
ATmega8A, ATtiny1634, ATtiny828, ATxmega128A3U, ATxmega128A4U, ATxmega128B1,
ATxmega128B3, ATxmega128C3, ATxmega128D4, ATxmega16A4U, ATxmega16C4,
ATxmega192A3U, ATxmega192C3, ATxmega256A3BU, ATxmega256A3U, ATxmega256C3,
ATxmega32A4U, ATxmega32C4, ATxmega384C3, ATxmega384D3, ATxmega64A3U,
ATxmega64A4U, ATxmega64B1, ATxmega64B3, ATxmega64C3 and ATxmega64D4.
bug #42085:  rename FUSE_HFUSE_DEFAULT to HFUSE_DEFAULT.
bug #42084: update LFUSE_DEFAULT in iotn84a.h as per datasheet
bug #40003: cast expression to required destination type to avoid inefficient code by gcc
bug #42024: fix typo in avrtiny macro
bug #40206: write to SPL and then SPH for xmega SP initialization (consistent with what compiler does for function prologues)
bug #39049: Add clock_prescale_set and get function/ macro for tiny 4/5/9/10/20 and 40 devices
bug #37103: Add wdt_enable and wdt_disable macros for ATtiny4/5/9/10/20/40 devices
bug #35498: fix a typo in util/setbaud.h