v3.26.2: Backport HH\Lib\Ref

This release backports the HH\Lib\Ref<T> class from later versions.

v3.26.1 is a bad release created from the wrong branch, and should not be used.

4.5.1: backport HH\Lib\Ref<T>

This release backports the HH\Lib\Ref<T> class from later versions.

4.1.1: Backport HH\Lib\Ref<T>

This release backports the HH\Lib\Ref<T> class from later versions.

4.0.3: Backport HH\Lib\Ref<T>

This release backports the HH\Lib\Ref<T> class from later versions.

4.0.2 is a bad release created from the wrong branch.

3.27.3: Backport HH\Lib\Ref<T>

This release backports the HH\Lib\Ref<T> class from later versions.

4.40: reduced memory usage of Async\Semaphore, removed redundant generics from C\count

This release:

• improves the memory usage of Async\Semaphore
• removes the generic from C\count(); this has no effect on most calls, however this change does strictly break backwards compatibility: if you are explicitly calling as C\count<SomeType>(), you will need to remove the generic from the call.

Remove `Tuple\from_async`, add `C\is_sorted` and `C\is_sorted_by`, support current nightlies

This release:

• removes Tuple\from_async; use concurrent { $a = await foo(); $b = await bar(); } or $tuple = tuple(await foo(), await bar()) instead. concurrent blocks should be preferred, but awaitable expressions can be used if a tuple is desired
• adds C\is_sorted() and C\is_sorted_by()
• improves the safety of keyset optimizations in C\contains
• optimizes several Str\ functions when $offset is 0
• supports current nightly builds of HHVM/HAck, and is expected to support HHVM 4.36.0. HHVM 4.25.0+ remain supported by this release

4.25.2: now compatible with both future and past versions of HHVM

remove lies_we_tell_hack.hhi from HSL (#83)

Summary:
Pull Request resolved: https://github.com/facebook/fbshipit/pull/83

Pull Request resolved: https://github.com/hhvm/hsl-experimental/pull/76

Pull Request resolved: https://github.com/hhvm/hsl/pull/98

In HSL and open-source projects that depend on it, most of these "lies" are unneeded, and the remaining places that depend on them can be avoided by changing `\HH\InvariantException` to `InvariantException`. Without namespace, it will always be correctly resolved to wherever HHVM autoimports it from.

"wherever HHVM autoimports it from" is actually changing (it used to be `\InvariantException` but is `\HH\InvariantException` as of a few days ago), which is the reason why this file is problematic. Before the HHVM change, and without the diff, the file was needed -- but after the HHVM change, the file causes Hack errors in HSL and [anything that depends on it](https://travis-ci.org/hhvm/)).

Reviewed By: fredemmott

Differential Revision: D18121499

fbshipit-source-id: abd73c9f72401755ae1250302bb4c515faf23e75

4.25.1: support HHVM 4.29+ and current nightlies

Remove fake InvariantException declaration

Summary: This was added to get around the inconsistency in how the typechecker and compiler viewed autoimporting. But this should only be enabled in OSS, not WWW.

Reviewed By: DavidSnider

Differential Revision: D18069991

fbshipit-source-id: ad45b372263bb3003650113bbc9d36229fc80e88

4.25: feature release

This release:

• adds the Async\Poll, Async\Semaphore, and Async\Condition classes, previously in hsl-experimental; these are best avoided where possible - e.g. one-at-a-time queues can be built by waiting on the previous stored awaitable instead of using these classes.
• adds Math\is_nan() and the Math\NAN constant
• adds Dict\shuffle()
• separates type parameters for C\contains and C\contains_key;
• supports and requires HHVM 4.25 and above