TEAL: AC fixed bid contract

[stefdegroot]

Create and test a fully featured TEAL 6 contract of a fixed price listing with prices in any ASA.

Features:

• Build with a single stateful contract
• Buyer pays to the contract itself for individual shareholder claims
• claim functions for all shareholders
• configurable payout address
• configurable shares
• Multi-asset buying and listing (more than one token can be bought or listed at once in the same contract)
• Extract tokens function
• Deposit tokens function
• close out as a separate function

Tasks:

• create TEAL contract
• test all TEAL routes on Testnet