Fix JsonIn::line_number to work correctly on all platforms.
Better JsonIn error messages when EOF reached prematurely.
JsonIn: use peek() in stead of stream->peek() for simplicity.
JsonIn: change stream->beg to std::istream::beg for explicitness.
Move files loaded by init.cpp to new directory "data/json".
Convert dreams.json to JsonObject loading (and restyle).
Violate style guidelines for readability.
Add a stub to init.cpp for initializing data structures if needed.
Convert mutations.json to dynamic loading.
Change dream.message ~> dream.messages as it's a vector.
Fix trait.visiblity ~> trait.visibility even if nothing uses it.
Merge branch 'master' into json_mut

Conflicts:
	data/json/mutations.json
Added framework for vehicle horns
Convert snippets.json to dynamic loading.
Add has_member method to JsonObject.
Dynamic loading for item_groups.json.
Dynamic loading for recipes.json.
Better access protection for JsonArray.
Armored car .json style

The armored car, in all it's json-y glory!
Condensed milk!