Updated nlohmann json library

Uses the latest and the greatest nlohmann json lib 3.9.1

Removed use of deprecated BIO_f_base64

There has been few issues reported for the use of BIO_f_base64 which has been deprecated by boringssl. Removed that dependency with the JWT base64 implementation.

Conan support and improved cmake build

Thanks to @gocarlos effort, we have now (Copied shamelessly from the PR request):

installation of header files
make tests and examples optional
clean up compiler flags -> make it possible compile on mscv
make vendored json version optional -> important for software clearing in some corporations
added conan support and build instructions

Fixed jwt_object compilation issues

1b105f4 introduced compilation regression with C++14/17 flags. Fixed it.

See #37

Build improvements and bug fixes

Fixed compiler warnings with pedantic mode enabled. Thanks to Samer Afach.
Added ES256/384 verification test.
Fix a major error in error_code category checking implementations. Thanks to Samer Afach.
Setting verify to false in decode will not do signature verification, This could be a breaking change.

VS2017 support

• Thanks to issues raised by @Sarbjit (Issue #11, #12, #13), VS2017 is also supported now.
• Fixed compilation of internal tests (Issue #9 ).

Support for latest OpenSSL versions

See #5 for more details.
Some structures were made private and some APIs were deprecated with OpenSSL 1.1.x version

First release of cpp-jwt

First release of cpp-jwt