Removed the dependency on GNATCOLL, and only left the one truely
essential for us, namely GNATCOLL.JSON. It is included indirectly
via libesl, which describes how to workaround potential issues.

From now on, this server only needs libesl, and AWS to build,
which hopefully should make it a lot simpler to build.
Merge branch 'master' of github.com:AdaHeads/Alice