Make Jetton Great

Teams start playing around with the jetton minter contract. Dropped by the core devs earlier this month, some folks decided to customize it a bit.

For example, the @bitoneng team introduced a series of improvements to the source code (made available on GitHub). Among these:

- the STR (send to receive) mechanism that enables users to simply send $TON and receive jettons in return instantly;
- withdraw $TON any time from the minter contract;
- limit ICO time / max. token amount;
- adding Fift scripts;
- code refactoring.

The repository is not production ready yet, but the devs are welcome to examine the lines.