Wire rework

[MX682X]

Alright, so kinda big changes:

• pulled twi.c into Wire.cpp, the seperation wasn't needed
• Master and Slave don't have seperate tx and rx buffers anymore, as the mode of operation is defined by the read/write bit so there is no interfereing between tx and rx between start and stop (saves like 50% of ram)
• reworked the slave isr routine to save some flash (a fresh look helps a lot)
• added masterTransmit/masterReceive functions that write directly to a user buffer (useful if you are tired of the Arduino API)
  • the Arduino API are basically just wrappers for this functions now
• replaced the define BUFFER_LENGTH with TWI_BUFFER_LENGTH (maybe WIRE_BUFFER_LENGTH would be better?) while maintaining backwards capability

[MX682X]

gonna finish updating the docs a bit later

[mikrocoder]

Hi,
Very nice.
TWI_BUFFER_LENGTH is the better name.
WIRE_BUFFER_LENGTH could be confused with OneWire.
My opinion.

[MCUdude]

I've been using TWI_BUFFER_SIZE for the last four years with MegaCoreX. It could be a good idea to keep the names similar.

[SpenceKonde]

Sorry for the awful delay here, have been moving between shitty temporary locations cause my roommates fucked me over and didn;t tell me they weren't re-signing lease.... half an hour before they told the land lord.

[MX682X]

Yeah, that soubds awful. I hope you were able to find something stable.

However it would be good to read your thoughts aswell about the Naming of the define. We have two options....