Cairo-lang

**StarkNet**:

* Replace block id with block hash (not verified by the OS yet)
* Add constructor arguments to the computation of the contract's address
* Add `get_transaction_receipt` command to the `starknet` CLI
* New system calls:
* `get_contract_address` - returns the address of the current contract
* `get_sequencer_address` - this may be used in the future for paying fees
* `delegate_call` - partial support

**Cairo**:

* Add `dw` keyword for defining constant arrays

**Cairo**

* In simple cases that do not involve if blocks and jumps, the compiler can automatically decide to create local variables for references that would have otherwise been revoked.

Small bug fixes.

**StarkNet**

* Contract constructors
* Identify transactions by their hash (replacing transaction id)
* `storage_ptr` was merged into `syscall_ptr` (you should now use `syscall_ptr` to access storage)
* Separate signature information from the transaction calldata
* Change the way contract addresses are computed
* Support arrays in return values of external functions
* Local testing infrastructure:
* Support passing structs
* Allow specifying caller address
* Support L1<->L2 messages
* Expose the transaction's required resources
* Technical modifications:
* Data availability format includes constructor arguments
* The format of the contract definition hash has changed
* Add L1 events when L1<->L2 messages are consumed

**Cairo**

* Improve compilation time
* Add a syntax for short strings (strings that fits into a single `felt`)
* Remove the python literal syntax (``%[ ... %]``) to allow safer compilation

* Support returning structs in `external` functions.
* Bug fixes.

**StarkNet**

* External functions
* Support tuples and structs in arguments
* Unit test infrastructure
* Better interface
* Support for python3.8
* Support specifying the Cairo path