requirement for status list size

[paulbastian]

As we declined to include a size property to the status list, we do not have other means than to decode&decompress the encoded status list and get status list size from the byte array length/size:
status list size = byte array size * 8 / bits
Therefore it makes to add the requirement that status list size must "fill up" to bytes

[paulbastian]

ready for PR after #57

[paulbastian]

Editors Call:

• only danger that we currently see is that some bits at the end have random/un-assigned values
• leaving this open for now

[paulbastian]

Editors Call:

• maybe add this as a recommendation in implementation consideration