* [x] make stringifier type * [x] make `toString` templated function * [x] auto-define type for * [x] `std::to_string` implementations * [ ] `.c_str()` * [ ] `.str()` * [ ] `.toString()` * [x] auto define `operator<<` for `std::ostream` * [x] auto define `std::to_string` for types that can `toString`