Add options to link against external JSON libraries
This adds two options to the CMake config:
`CPPDAP_USE_EXTERNAL_NLOHMANN_JSON_PACKAGE` and `CPPDAP_USE_EXTERNAL_RAPIDJSON_PACKAGE`
If either of these is set, instead of using the json submodule, the build will be configured by using `find_package()` and linking against the specified JSON library.
CMake installation target has been broken for years.
cppdap is only internally used and tested as a library that is included as a sub-module of another project.
In order for a package to be installable, it really needs a stable ABI / API, which we've made no explicit guarantees about.
cppdap is small enough that it can easily be included in a third_party directory of another project.
Remove the broken, unmaintained installation rules.
Fixes: #54
If any of the `CPPDAP_?SAN` sanitizers are enabled, then the build would fail as the compile flags would collide with hard-coded use of address sanitizer for the fuzzer.
Don't hard code address sanitizer for the fuzzer - just use the CMake flag options.
`DAP_IMPLEMENT_STRUCT_TYPEINFO_EXT` and `DAP_STRUCT_TYPEINFO_EXT` are two new flavors of `DAP_IMPLEMENT_STRUCT_TYPEINFO` and `DAP_STRUCT_TYPEINFO` that allow you to derive message types.
This involved a bit of reworking on the serializer interfaces.
Added test.
Issue: #32
Without this the vscode extension cannot find the example executable, and the example fails.
Also use $USERPROFILE instead of $HOME for finding the `.vscode` user directory for installing the extension.
Bug: #12
`nlohmann/json` raises a `size_t` to `int` MSVC warning that will fail the build if `CPPDAP_WARNINGS_AS_ERRORS` is enabled.
Given that this is not our code, the best we can do is to make an exception for this warning.
