Token vesting contract

Goal

• Simple vesting contract (SVC) that allows you to deposit X SPL tokens that are unlocked to a specified public key at a certain block height/ slot.
• Unlocking works by pushing a permissionless crank on the contract that moves the tokens to the pre-specified address
• Token Address should be derived from https://spl.solana.com/associated-token-account
• 'Vesting Schedule contract' - A contract containing an array of the SVC's that can be used to develop arbitrary- vesting schedules. (?)
• Tooling to easily setup vesting schedule contracts
• Recipient address should be modifiable by the owner of the current recipient key
• Implementation should be a rust spl compatible program, plus client side javascript bindings that include a CLI- interface. Rust program should be unit tested and fuzzed.

Structure

• cli : CLI tool to interact with on-chain token vesting contract
• js : JavaScript binding to interact with on-chain token vesting contract
• program : The BPF compatible token vesting on-chain program/smart contract

TODO: Open issues for the following bugs

• Instruction::new serializes vector data wrongly (adds vector length as prefix to byte array)
• solana-program-test/lib.rs - invoke_signed - Order of accounts matters. Writability is either not checked or falsely assumed for system program.