Improve code examples + snippets

[denalimarsh]

Updates transfer example and adds snippets for creating, claiming, and refunding a bep3 swap on Kava.

[thomasmost]

When I run npx ts-node example/transfer.ts I get

Error: mnemonic cannot be undefined
    at KavaClient.setWallet (/Users/thomas/kava/javascript-sdk/src/client/index.ts:145:13)
    at /Users/thomas/kava/javascript-sdk/example/transfer.ts:14:14
    at step (/Users/thomas/kava/javascript-sdk/example/transfer.ts:33:23)
    at Object.next (/Users/thomas/kava/javascript-sdk/example/transfer.ts:14:53)
    at /Users/thomas/kava/javascript-sdk/example/transfer.ts:8:71
    at new Promise (<anonymous>)
    at __awaiter (/Users/thomas/kava/javascript-sdk/example/transfer.ts:4:12)
    at main (/Users/thomas/kava/javascript-sdk/example/transfer.ts:9:12)
    at Object.<anonymous> (/Users/thomas/kava/javascript-sdk/example/transfer.ts:44:1)

Can you add to the README steps for properly running the examples? I feel like I must be missing something

[fwiessner]

kavaClient.setWallet(Env.KavaDeputy.Local.Mnemonic);

and

let acc = await kavaClient.getAccount(Env.KavaDeputy.Local.Address);

is wrong - must be Env.KavaAccount.Local.Mnemonic and Env.KavaAccount.Local.Address !