Also mention dependency on OpenSSL in Readme and software manual

because IRLP are also labelled "long-term"

Specification requires initialization with bits equal to "1"

Due to the processing order of the decoder, NAL units always need to be stored, because the decoder
does not know yet, whether DSCI has arrived.

Also contains small fixed in error messages.

Ported from JVET-TuC with small improvements on certificate handling