added json list in a similar fashion to json object
renamed object_type to object
updated readme, index.html, and json.md to include objects and lists
updated examples to be slightly cleaner and include lists
replaced instances of json object (std::map and such) with the short version (object)
accurate floating point number dumping (`6.0` instead of `6`) while taking 1/30th of the time (29 microseconds saved)
added json list testing
snuck in utf-8 middleware warning fix
snuck in twitter card style for crowcpp.org site (makes social media cards look way better with a large image)
