[ADC 1.0.4] UTF-8 encoding clarification

Given the discussion in 4-byte utf-8 and DC software the following is a proposal to change the text in the ADC document to fully specify encoding:
From:

All text must be sent as UTF-8 encoded Unicode in normalization form C.

to

All text must be sent as 1-to-4 byte, RFC 3629-compliant UTF-8 encoded Unicode in normalization form C.

I have pushed this so this will be part of ADC 1.0.4.