We totally forgot to implement the comparison operators other than ==
and != for scalar types. Consequently, comparing a JSON value with a
scalar type led to compile errors.

add enum class default conversions

Properly pop diagnostics

The implementation is non-standard. Deprecation allows a simpler API in
the future without removing any features.

NaN values never compare equal to themselves or to other NaN values.

https://blog.travis-ci.com/2017-03-28-xcode-83-ga-is-here

We now only demand our exceptions to be is_nothrow_copy_constructible
if std::runtime_exception is.

The solution with a std::runtime_error member is more elegant. It
allows to have std::exception as base class again. However, I still
have no idea why GCC thinks the copy constructor may throw...

To have nothrow-copy-constructible exceptions, we inherit from
std::runtime_error which can cope with arbitrary-length error messages.
Intermediate strings are built with static functions and then passed to
the actual constructor.

Add Visual Studio 17 image to appveyor build matrix

UTF8 encoding enhancement

Fix typo

The result of snprintf is later used in situations where a long may
overflow.

Make exception base class visible in basic_json

Instead of overwriting src/json.hpp with an empty file

Added catch branch for out_of_range exception that can occur if input
file contains a number overflow.

We should compare the binary serializations rather than the JSON values
themselves. This fix was already done for CBOR and apparently forgotten
for MessagePack.

🎨 Namespace `uint8_t` from the C++ stdlib

add to_json method for C arrays

- Removed unused headers.
- Added override where needed.
- Added description for parse_error.113 exception.
- Fixed some conversion warnings.
- Integrated cbor_expect_string function for CBOR maps.
- Added documentation on the supported CBOR/MessagePack features.
- Added test to check all initial bytes for CBOR input.

With GCC 7, there are even more diagnostic flags.