Merge branch 'development' into fix/instant/signature-denied

* development: (914 commits)
  Unfix compiler version except for top level contracts
  Move OrderValidator to extensions
  Update CHANGELOG
  Remove assembly version of matchOrders
  Add getOrderInfo check before calling fillOrder
  Update comments and hard code function selector constants
  Fix build after rebase
  update comments
  Fix build and add back tests
  Update dependency paths
  Add OrderMatcher tests
  feat: Add OrderMatcher contract that takes spread in multiple assets by calling `matchOrders` followed by `fillOrder`
  Update CHANGELOG
  Use more efficient equality checks
  Add note about input validation
  Use more efficient check for overflow
  Check if amount == 0 before doing division
  Reapply prettier
  New relayers
  feat(sra_client.py): Test deployed pkg via tox
  ...

1 files changed, 14 insertions, 1 deletions

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 1fea8f501..3e709b36f 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -79,7 +79,20 @@ If using the Atom text editor, we recommend you install the following packages:
 *   VSCode: [prettier-vscode](https://marketplace.visualstudio.com/items?itemName=esbenp.prettier-vscode)
 *   Atom: [prettier-atom](https://atom.io/packages/prettier-atom)
 
-## Fix `submit-coverage` CI failure
+## Unenforced coding conventions
+
+A few of our coding conventions are not yet enforced by the linter/auto-formatter. Be careful to follow these conventions in your PR's.
+
+1.  Unused anonymous function parameters should be named with an underscore + number (e.g \_1, \_2, etc...)
+1.  There should be a new-line between methods in a class and between test cases.
+1.  If a string literal has the same value in two or more places, it should be a single constant referenced in both places.
+1.  Do not import from a project's `index.ts` (e.g import { Token } from '../src';). Always import from the source file itself.
+1.  Generic error variables should be named `err` instead of `e` or `error`.
+1.  If you _must_ cast a variable to any - try to type it back as fast as possible. (e.g., `const cw = ((zeroEx as any)._contractWrappers as ContractWrappers);`). This ensures subsequent code is type-safe.
+1.  Our enum conventions coincide with the recommended Typescript conventions, using capitalized keys, and all-caps snake-case values. Eg `GetStats = 'GET_STATS'`
+1.  All public, exported methods/functions/classes must have associated Javadoc-style comments.
+
+### Fix `submit-coverage` CI failure
 
 If you simply fork the repo and then create a PR from it, your PR will fail the `submit-coverage` check on CI. This is because the 0x CircleCI configuration sets the `COVERALLS_REPO_TOKEN` environment variable to the token for `0xProject/0x-monorepo`, but when running the check against your fork the token needs to match your repo's name `your-username/0x-monorepo`.