magically hex TDT ID if given in decimal

[brandoncurtis]

TDT IDs are given in decimal in many block explorers: https://ropsten.etherscan.io/token/0x20ea5b307ee28eefc15a3e6d945c5e8da5a8add9

If a decimal TDT ID is provided, automatically convert from decimal to a hex address.

[mhluongo]

Ooh good idea, thanks @brandoncurtis!

[Shadowfiend]

Feels like we could rework this somewhat like:

let address = evt.target.value
let isValid = web3.utils.isAddress(address)

try {
  // Handle non-hex values that are BN-convertible.
  address = '0x' + web3.utils.toBN(evt.target.value).toString(16)
  isValid = web3.utils.isAddress(address)
} catch (_) {}

this.setState({
  depositAddress: address,
  depositAddressIsValid: isValid,
  depositAddressHasError: ! isValid,
})

This feels a little safer; for a (very contrived) example that would pass the PR's current test, the user could enter The dog is a wee fox (or any 20-character string) and toHex would happily convert it to hex and isAddress mark it as valid.