String tokenization

Command tokenization.

Complete command is a string that is finalized by '\n' << STATS sys

>> +OK stats

If there is a blob field it can be specified as an array: $LENGTH[space]CONTENT

<< CTX test PUSHFRONT ID ABC123 CONTENT 2 01234567890ab ASYNC DEFD1234 WC RC \n

>> +OK ASYNC DEFD1234

<< SET CTX test

>> +OK

<< PUSHFRONT ID ABC123 CONTENT 2 01234567890ab ASYNC DEFD1234 WC RC \n

>> -ERR:300:Message with such ID already exists\n