ngtcp2 for Nim

Wrapper around the ngtcp2 C library for Nim.

Updating to a newer version

Follow these steps when updating the wrapper to a newer version of ngtcp2:

• update the git submodule in libs/ to point to the new version
  • git submodule update --init --recursive
• run build.sh (requires Nim, CMake and clang to be installed)
• increase the version property in the ngtcp2.nimble file
• commit the changes

Enabling QuicTLS

`-d:ngtcp2_enable_quictls`