fixed race condition that was hanging transmission at the first packed
fixed race condition that was hanging transmission at the first packed

Not big enough RX fifo was getting overflown during 1 sec delay.
Timeouts could request packet retransmissions until receiving whole
packet, but it is still not implemented.

Also, some minor fixes.

jnk0le/Easy-AVR-USART-C-Library,jnk0le/AVR-UART-lib