eolib v0.1.0-beta.3

Added

• An API reference site at https://ethanmoffat.github.io/eolib-cpp/, built with Doxygen, with a summary page, the
  getting started guide, namespace descriptions and a version picker. It has the newest release of each minor version.
  Each release also includes the docs as eolib-<version>-docs.tar.gz.
• EOLIB_BUILD_DOCS CMake option (off by default), which adds a docs target that builds the API reference.
• scripts/serve-docs.sh, which builds the docs site for the working tree and serves it on localhost.
• scripts/install-deps.sh --docs and scripts/install-deps.ps1 -Docs install Doxygen into .tools/bin.
• PacketFactory::Contains(family, action) for client and server packets, which checks whether a packet exists for a family and action without creating it. It is generated from the protocol files, like Create.

Fixed

• Protocol comments containing #, @ or \ are escaped in the generated documentation comments, so Doxygen shows
  them as written instead of treating them as commands or links (e.g. #nowall).