Memory consumption
baseline is the test program using a library with empty function bodys.

		ATmega328	ATmega256	ATtiny85	ATtiny84
baseline	1022+9		1540+9		756+9		772+9
softi2c		1504+9 +482	1988+9 +448	1184+9 +428	1200+9 +428
softi2cpt	1586+9 (+82)	2068+9	(+80)	1266+9 (+82)	1282+9 (+82)
hardi2c		1456+9 +434	1934+9 +394     ------          -----
softwire	2088+75	+1066	2560+75		1758+75	+1002	1774+75
slowsoft	1996+13	+974	2408+13		1488+13	+732	1504+13
slowwire	2578+79	+1556	2986+79		2048+79	+1292	2100+79
usiwire		-------		------		1864+54	+1108	1958+54
tinywire        -------		------		2590+95	+1834	-------
wire		2814+219 +1972	3304+219	-------         -------