added e6-style definitions for Timer/Counter3 on 1284p
added e6-style definitions for Timer/Counter3 on at90can32/64/128
fixed bit names for COM3An
fixed use of register names TCCR1A/B and MCUCSR, added e6-style definitions for Timer/Counter3 on atmega162
fix bitmask for TC1/TC3_PRESCALER_64 for at90can32/64/128
fixed bitmasks for TCn_PRESCALER_xy
fixed bitmasks for TCn_PRESCALER_xy
fixed bitmasks for TCn_PRESCALER_xy
fixed use of register names TCCR1A/B, fixed TCn_PRESCALER_xy bitmasks, added e6-style definitions for Timer/Counter3 on atmega64
fixed TCn_PRESCALER_xy bitmasks, added e6-style definitions for Timer/Counter3 on atmega128
fixed Timer/Counter3 TIMSK and TIFR bits
whitespace cleanup
removed redundant define MCU_HAS_TC3
Merge pull request #226 from michaelb42/e6_add_Timer_Counter3_support

Add Timer/Counter3 support, fix issues #223 and #225 for several controllers