attribution text and funder acknowledgement for text reuse

[lcerrato]

See PerseusDL/lexica#3

I'm seeing questions on reuse that used to be answered within the xml headers (preferred credit line, attribution info, etc.). We offered something like this in the download version of the texts, where it says what we prefer to remain in the header, expands the funder entity, etc.

Basically, all of the entities were spelled out:

&responsibility;
&fund.NEH;
&Perseus.publish;
etc.

It may be time to revisit this to alleviate confusion.