Make --verbose and --model options global

This patch adds the attribute 'global = true' for the top-level
--verbose and --model options, which ensures that they can also be set
for subcommands.  For example:
  $ nitrocli status --model pro
Instead of only:
  $ nitrocli --model pro status

CHANGELOG.md

@@ -5,6 +5,7 @@ Unreleased
  - Added `structopt` dependency in version `0.3.7`
  - Replaced `argparse` with `structopt`
  - Removed `argparse` dependency
+ - Made the `--verbose` and `--model` options global
 - Removed vendored dependencies and moved source code into repository
  root
 - Bumped `nitrokey` dependency to `0.5.1`

src/args.rs

@@ -74,10 +74,10 @@ impl<'io> Stdio for ExecCtx<'io> {
 #[structopt(name = "nitrocli")]
 struct Args {
  /// Increases the log level (can be supplied multiple times)
- #[structopt(short, long, parse(from_occurrences))]
+ #[structopt(short, long, global = true, parse(from_occurrences))]
  verbose: u8,
  /// Selects the device model to connect to
- #[structopt(short, long, possible_values = &DeviceModel::all_str())]
+ #[structopt(short, long, global = true, possible_values = &DeviceModel::all_str())]
  model: Option<DeviceModel>,
  #[structopt(subcommand)]
  cmd: Command,