Merge branch 'master' into dp/chore/fetch-dependencies-from-crates

* master: (22 commits)
  Introduce treasury and document (#646)
  Off-the-table staking preference (#656)
  Implement function `json_metadata` in `decl_module!` (#654)
  Fix warnings in networking (#652)
  Add a reputation system (#645)
  Check for pruned block state (#648)
  Contract runtime polishing (#601)
  WIP on chain heap (#639)
  Events to track extrinsic success (#640)
  Install llvm-tools-preview component (#643)
  fix wasm executor compile error (#631)
  random fixes (#638)
  Empty becomes (), reflecting convention (#637)
  Allow to build_upon skipped entries, but don't walk back (#635)
  Separate out staking module into balances and payment (#629)
  Update .gitlab-ci.yml (#633)
  Do not attempt to rustup if in CI. This is taken care of by the base (#621)
  Avoid need for ident strings in storage (#624)
  rename to panic_handler as panic_implementation is deprecated in nightly (#626)
  5 random fixes (#2) (#623)
  ...