str_replace with empty array should return array

Handle empty array in str_replace like Zend and return an empty
array instead of null.

Closes #1452

Reviewed By: @alexmalyshev

Differential Revision: D1112243

Pulled By: @scannell
Fix preg_match_all requiring three parameters

preg_match_all's third parameter ($matches) should be an optional parameter.

Closes #1451

Reviewed By: @alexmalyshev

Differential Revision: D1112209

Pulled By: @scannell
Add Array to string conversion notice

Add Array to string conversion notice (and RaiseNotice IR
instruction needed to do so when using the JIT)

Closes #1314

Reviewed By: @alexmalyshev

Differential Revision: D1080985

Pulled By: @scannell
Change hasInternalReference to DataWalker and track more info of the object graph

Change, centralized and abstracted data graph walker to collect some info on the data graph for APC

Reviewed By: @jdelong

Differential Revision: D1098889
Separate bits for "non ref count" and "static" types.

Use different bits for static type and ref counted types. Every static type is not ref counted however we want to introduce the concept of a non static type that does not need ref counting.

Reviewed By: @markw65

Differential Revision: D1090994
Clean json_last_error() when parsing non-objects

JSON_parse() regards scalars as a syntax error,
but we have explicit checks for null, true, false,
numerics, and strings.  Clear the error when we return these.

Reviewed By: @scannell

Differential Revision: D1112796
Run a double-quoted json scalar string through the parser

The non-JSON fallback for quoted string values
should still respect JSON string encoding rules like
unicode, and printf-style escape sequences.

Reviewed By: @scannell

Differential Revision: D1112801
Merge branch 'master' of https://github.com/facebook/hhvm