improved doc
improved doc


Former-commit-id: 36b994245a5f57381776f5cb0bb53d7b13a0dd67 [formerly 36b994245a5f57381776f5cb0bb53d7b13a0dd67 [formerly 3bc585cc8bba11de863594ad848dffc2a2fb84df]]
Former-commit-id: b7107c392077e39a28a3fed5b1c17133a34ba2ba
Former-commit-id: 9f8b5a58a68c7c9e9299ef8f220899279515afbf
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine