An optional parameter for dump() allows to set the character to use for
indentation (default: space). In case a JSON value is serialized to an
output stream, its fill character is used (and can be set with
std::setfill).
- Added comments for the serializer class.
- Added test case for resizing of the indentation string.
- Using std::none_of to check if “.0” needs to be added to
floating-point number.