message: Add a few more explicit result types
diff: @@ -83,10 +83,10 @@ pub fn transfer<S: Storage, A: Api, Q: Querier>(
  let sender_raw = deps.api.canonical_address(&info.sender)?;
  let mut accounts = balances(&mut deps.storage);
  - accounts.update(sender_raw.as_slice(), |balance: Option<Uint128>| {
  + accounts.update(&sender_raw, |balance: Option<Uint128>| {
  balance.unwrap_or_default() - send
  })?;
  - accounts.update(rcpt_raw.as_slice(), |balance: Option<Uint128>| {
  + accounts.update(&rcpt_raw, |balance: Option<Uint128>| -> StdResult<_> {
  Ok(balance.unwrap_or_default() + send)
  })?;
  @@ -169,7 +169,7 @@ pub fn bond<S: Storage, A: Api, Q: Querier>(
  totals.save(&supply)?;
  // update the balance of the sender
  - balances(&mut deps.storage).update(sender_raw.as_slice(), |balance| {
  + balances(&mut deps.storage).update(&sender_raw, |balance| -> StdResult<_> {
  Ok(balance.unwrap_or_default() + to_mint)
  })?;
  @@ -212,12 +212,12 @@ pub fn unbond<S: Storage, A: Api, Q: Querier>(
  // deduct all from the account
  let mut accounts = balances(&mut deps.storage);
  - accounts.update(sender_raw.as_slice(), |balance| {
  + accounts.update(&sender_raw, |balance| -> StdResult<_> {
  balance.unwrap_or_default() - amount
  })?;
  if tax > Uint128(0) {
  // add tax to the owner
  - accounts.update(invest.owner.as_slice(), |balance: Option<Uint128>| {
  + accounts.update(&invest.owner, |balance: Option<Uint128>| -> StdResult<_> {
  Ok(balance.unwrap_or_default() + tax)
  })?;
  }
  @@ -239,7 +239,7 @@ pub fn unbond<S: Storage, A: Api, Q: Querier>(
  totals.save(&supply)?;
  // add a claim to this user to get their tokens after the unbonding period
  - claims(&mut deps.storage).update(sender_raw.as_slice(), |claim| {
  + claims(&mut deps.storage).update(&sender_raw, |claim| -> StdResult<_> {
  Ok(claim.unwrap_or_default() + unbond)
  })?;
  @@ -287,7 +287,7 @@ pub fn claim<S: Storage, A: Api, Q: Querier>(
  })?;
  // update total supply (lower claim)
  - total_supply(&mut deps.storage).update(|mut supply| {
  + total_supply(&mut deps.storage).update(|mut supply| -> StdResult<_> {
  supply.claims = (supply.claims - to_send)?;
  Ok(supply)
  })?;
  