4.0.0-beta.3: One bug fix, and improvements

chore(examples): Add example for smart contract interaction
feat(michelson-encoder): Better support for various tokens …
refactor(tezos-ts): Add constant for default fee, gas and storage limit
fix(tezos-ts): Mutez conversion was flipped in transfer function …
Merge pull request #61 from ecadlabs/add-constants-for-default-gas-fee …
Merge pull request #63 from ecadlabs/michelson-encoder-tokens-improve… …
Merge pull request #62 from ecadlabs/fix-flipped-mutez-conversion …