wsly 1.2.0

• Reduce startup latency by loading interactive Bash configuration only once
  per wsly Bash process and caching the helper path for each PowerShell session
  and WSL distro.
• Cache identical Bash completion requests for 10 seconds.
• Add -Timing / -t timing diagnostics and -Quiet / -q to suppress
  interactive startup status messages.
• Make local release packaging work when Windows PowerShell is launched from a
  WSL checkout.