Platformio+Digispark compatible solution

[dontsovcmc]

I want to use CmdMessenger with Digispark attiny85.

They have their own Stream class, Print classes.. .

1. First of all I add some functions to Stream class.

int timedRead()
virtual size_t readBytes(char *buffer, size_t length)

2. I spend a lot of time to find a problem why CmdMessenger can't hear me (only UnknownCommand handler called) ... (I connect Arduino to COM port and want to send-receive bytes in Terminal)

I was angry when I found solution:

Send command 0 
30 3B
Receive command 1
01 2C 33 3B

Digispark made print function without default argument=DEC... for all types except char..
For compatible we should add DEC everywhere in CmdMessenger :(.

comms->print(cmdId, DEC);

and etc

3. Attiny85 doesn't want to start with CmdMessenger cause little memory.
   I change defines:

#define MAXCALLBACKS        5   // The maximum number of commands   (default: 50) 
#define MESSENGERBUFFERSIZE 20   // The length of the commandbuffer  (default: 64)
#define MAXSTREAMBUFFERSIZE 20  // The length of the streambuffer   (default: 64)

and it works fine :)

There was difficult to find solutions cause:

1. There is no protocol description or trace. Please add them.
2. There is no tests written on "C" or "Python" :)

[dontsovcmc]

There are errors in Platformio libraries for "digispark-tiny" platform :(