Add static initializers to RippleSSLContext, fix book offers limit param

Whoa, took me a while to work out what I was seeing here, because the indenting is wrong... :-D

I also think you should extract a local variable:

auto& chron =  negotiationSet.chronological;

(As you know, I think we often use too many local variables, but in this case we use it a lot in a very short area...)