Improved

• carthage checkout now checks out dependencies concurrently for a nice speedup (#1910). Thanks @erichoracek!
• The notification that there’s a new Carthage version available is now printed to stderr instead of stdout (#1918). Thanks @BobElDevil!
• Carthage can now handle frameworks that have no debug symbols (#1932). Thanks @erichoracek!

Thank you to @ikesyo, @mdiep, and @erichoracek for improvements to the codebase! Thank you to @mdiep, @ikesyo, @jdhealy, and @BobElDevil for reviewing pull requests!