Before:
```
▶ target/debug/deno https://deno.land/std/examples/echo_server.ts
error: Uncaught PermissionDenied: run again with the --allow-net flag
► $deno$/dispatch_json.ts:40:11
at DenoError ($deno$/errors.ts:20:5)
at unwrapResponse ($deno$/dispatch_json.ts:40:11)
at sendSync ($deno$/dispatch_json.ts:67:10)
at listen ($deno$/net.ts:170:15)
at https://deno.land/std/examples/echo_server.ts:4:23
```
```
▶ target/debug/deno --allow-read=/usr https://deno.land/std/examples/cat.ts /etc/passwd
error: Uncaught PermissionDenied: run again with the --allow-read flag
► $deno$/dispatch_json.ts:40:11
at DenoError ($deno$/errors.ts:20:5)
at unwrapResponse ($deno$/dispatch_json.ts:40:11)
at sendAsync ($deno$/dispatch_json.ts:91:10)
```
After:
```
▶ target/debug/deno https://deno.land/std/examples/echo_server.ts
error: Uncaught PermissionDenied: network access to "0.0.0.0:8080", run again with the --allow-net flag
► $deno$/dispatch_json.ts:40:11
at DenoError ($deno$/errors.ts:20:5)
at unwrapResponse ($deno$/dispatch_json.ts:40:11)
at sendSync ($deno$/dispatch_json.ts:67:10)
at listen ($deno$/net.ts:170:15)
at https://deno.land/std/examples/echo_server.ts:4:23
```
```
▶ target/debug/deno --allow-read=/usr https://deno.land/std/examples/cat.ts /etc/passwd
error: Uncaught PermissionDenied: read access to "/etc/passwd", run again with the --allow-read flag
► $deno$/dispatch_json.ts:40:11
at DenoError ($deno$/errors.ts:20:5)
at unwrapResponse ($deno$/dispatch_json.ts:40:11)
at sendAsync ($deno$/dispatch_json.ts:91:10)
```
- Remove ability to specify run arguments like `--allow-net` after the
script argument. It's too hacky to make work with clap.
- Remove `--v8-options`, instead use `--v8-flags=--help`
- Give more descriptive names to unit tests in flags.rs
- Assume argv and subcommand into DenoFlags struct so the output of
flags module is only DenoFlags rather than the tuple (subcommand, flags,
argv).
- Improve CLI help text
- Make `deno run` specific args like `--allow-net` only show up in 'deno
help run' instead of as global flags in `deno help`.
- Removes `deno version` to simplify our implementation and be closer to
clap defaults. `deno -V` now only shows Deno's version and not V8's nor
TypeScript. `Deno.versions` can be used to see that information.
- Prevent clap from auto-detecting terminal width and attempting to wrap
text.
