Convert array_multisort to HNI

Summary: fixes #3993

Also removed all MixedVariableArugument flags because it's no longer used

Reviewed By: @sgolemon, @JoelMarcey

Differential Revision: D1621857

Signature: t1:1621857:1414521500:d1f977cecba55458b5e7c92f6c79a303a52f0f4c
Convert POSIX to HNI

Summary: fixes #3933

Reviewed By: @markw65

Differential Revision: D1604628

Signature: t1:1604628:1414799212:5aefd092bdc9a672b65f681b9597a7ef7b6c214b
Convert DOMDocument to HNI

Summary: fixes #3745

Reviewed By: @ptarjan, @JoelMarcey

Differential Revision: D1638235

Signature: t1:1638235:1414612822:fd550de38c1167d73edc2c0e7cfbb9cb6cbc058c
Remove the memelim store sinking code for now

Summary: It is broken, and the wrong way to do this.

Reviewed By: @alexmalyshev

Differential Revision: D1654600
Convert file to HNI

Summary: fixes #3911

Reviewed By: @markw65

Differential Revision: D1598886

Signature: t1:1598886:1414799275:43aa503a9711056138e6f570639a108281fbcbca
Fix infinite loop in hh --color.

Summary: My previous algorithm assumed an invariant that did not actually
hold. I've made that invariant hold, in addition to describing it explicitly
in a comment.

Reviewed By: @jwatzman

Differential Revision: D1654746
Fix hphpd crash when printing systemlib classes

Summary: fixes facebook/hhvm#4075

Reviewed By: @paulbiss

Differential Revision: D1642223
Convert smart_new to use smart_malloc()

Summary: We need headers on every object to make the heap parseable.

Reviewed By: @jdelong

Differential Revision: D1654899
Add ** operator to the hack typechecker

Summary: Add the exponential operator to the hack type checker

Reviewed By: @elgenie

Differential Revision: D1647793
Convert ext/spl to HNI

Fixes #3947
This was a missing clone in the assignment.
null_variant => null; only clone on objects