Prepare 0.17.4 release

[djc]

Fixes #541.

Changelog:

• Handle newline in msg and empty msg (Handle newline in msg and empty msg #540, thanks to RDruon)
• Handle terminal line wrap to avoid new line (Handle terminal line wrap to avoid new line #533, thanks to RDruon)
• Resetting the elapsed time also resets ETA (resetting the elapsed time also resets ETA #538, thanks to afontenot)
• Mention the prefix and message placeholders in the with_ docs (Mention the prefix and message placeholders in the with_ docs #529, thanks to lnicola)
• Allow rate-limiting TermLike targets (Allow rate-limiting TermLike targets #526, thanks to akx)
• Fix docs for ProgressDrawTarget (Fix docs for ProgressDrawTarget #523, thanks to tillarnold)
• Change "OS X" to "macOS" (Change "OS X" to "macOS" #519, thanks to atouchet)
• Fix MultiProgress alignment handling and migrate from structopt => clap (Fix MultiProgress alignment handling and migrate from structopt => clap #516)
• Don't deadlock when double-adding ProgressBar (Fix #503: don't deadlock when double-adding pb #515)
• Use instant::Instant when compiling to WASM (Use instant::Instant when compiling to WASM. #514, thanks to azriel91)
• Update portable-atomic requirement from 0.3.15 to 1.0.0 (Update portable-atomic requirement from 0.3.15 to 1.0.0 #512)
• inc() after work in examples (fix: inc after work #522, thanks to tatref)