* gaiad gentx subcommands refactoring
- Replace STDIN/STDOUT redirection in `gaiad gentx` with subcommands
command line options to redirect streams to file since viper does
not handle redirection well.
- Use `BuildCreateValidatorMsg` to build a `MsgCreateValidator` rather
than redirecting to `gaiacli tx stake create-validator`.
- `PrintUnsignedStdTx` now takes an `io.Writer` object.
- Mark `--pubkey`, `--amount` and `--moniker` as required flags
instead of validating them manually.
- Use stake.NewDescription() to make a new Description - ref #2835
* Refresh PENDING.md