Remove bad assert from BaseVector::data()

Summary: BaseVector::data() had an assert that was checking if m_data[0] was a Cell.
This assert is bogus because the Vector could be empty, and in such cases
it is not valid to dereference m_data[0]. It turns out that this assert was
redundant anywhere because the only place that uses BaseVector::data()
already asserts that each element in the Vector is a Cell (also, there are
a bunch of asserts throughout ext_collections that make sure that each
element is a Cell).

Reviewed By: @elgenie

Differential Revision: D1680393

Signature: t1:1680393:1415922724:0331eb4ed100231a24517cf4870736a07f56e275

EZC: Fix count() and conversion to boolean of ProxyArray

Fix JIT versions of count() and conversion of array to boolean, so
that they work with ProxyArray. In both cases, duplicate the logic in
ArrayData::size() -- if the sign bit of the size field is unset, use
that field, otherwise call vsize().

The resulting generated machine code for conversion to boolean is along
the lines of:

  mov    0x4(%rdi),%eax
  test   %eax,%eax
  js     0xf80049b
  setne  %al

where 0xf80049b is the slow path. This is similar to the machine code I
previously reported for ArrayData::size() in code review of 1717e028f18
(see facebook#3065).

Added test case which previously failed.

stop breaking ubuntu 10.04

Summary: A partial revert of facebook#3591 . I used `FindLibZip.cmake` as a template. I think for system defined libraries the old code was good enough, but if the thing is only installed in the CMAKE_INCLUDE_PATH then the macro@​radford was using won't work.

Reviewed By: @JoelMarcey

Differential Revision: D1560119

set version to 3.2

unit tests expected output fix for change in object destruction order

Summary: Fi unit tests expected output

Reviewed By: mwilliams

Subscribers: hphp-diffslists, ps

Don't build test binary by default.

Enable it with `cmake -DTEST_BIN=On .`

bump version to 3.0.0

Revert "Properly invoke setter/getter for unset declared properties"

This reverts commit 2638538.

bump version to 2.4.1

bump version to 2.4.0