v0.5: scheduled release

Highlights

• async functions are now released, e.g. Vec\filter_async(), Vec\from_async(), and Vec\map_aysnc(). Similar functions exist for the other collection namespaces.
• Str\split() and Str\join() are now temporarily deprecated as part of the work to switch their argument order for consistency (#3)

All Changes

• Use Str\split_args_switched in generate-docs.php by Kunal Mehta on 2017-09-27
• TEMPORARY: Deprecate Str\split by Kunal Mehta on 2017-09-27
• opensource the async functions by Fred Emmott on 2017-09-26
• Revert D5894620: remove the spaceship operator from the HSL implementation by Kunal Mehta on 2017-09-25
• Re-enable test case in DictOrderTest by Kunal Mehta on 2017-09-25
• Remove leading slashes from 'use' statements by Kunal Mehta on 2017-09-25
• remove the spaceship operator from the HSL implementation by Fred Emmott on 2017-09-22
• Str{join, split}_args_switched by Kunal Mehta on 2017-09-22