Update folly
Turn SrcRec

There's no compelling reason for this to be a fixed
constant. I also renamed EvalMaxTrans in an attempt to differentiate
it from the new option.
don't create an empty String

@mwilliams reminded me variables declarations actually make them.
stop spew

The open source build complains about these: https://travis-ci.org/facebook/hiphop-php
Fix printing of ActRecInfo

If it's an AR for a constructor, the high-order bit is set, and it gets printed
as -2 billion. This is confusing; at first I thought it was a bug. Print it out
in a readable way.
!bool != bool

I should have tested it :( While I was in there debugging I found some dead code

Closes #771
Use AtomicHashArray for PCRE
gen_systemlib.sh should use passed-in files

gen_systemlib.sh currently takes a list of input files and then ignores them
Fix idl generation

Make idl generation work; properly use hphp/ paths, tweak some
out-dated names, etc.
Treadmill for shared variants

Avoids atomic incRefs and decRefs. StringData no longer needs to
be sweepable for SharedVariants.
is_dir should be false for false

This is breaking Symphony
move test

StringBuffer is aparantly a facebook only thing
Refactor copyImpl() and nonSmartCopy()

I've done this refactoring without efficiency in mind - it's one of the steps toward more aggressive in-situ allocation. Yet to my surprise perflab rewarded this simple refactoring with a whopping decrease in I-TLB misses. I myself am wondering what has caused this. Anyhow let's run perflab once more and get this baby on the road.
Increase spill area

Bump it from 8 to 16 Cells.
Optimize ContSend, ContRaise, and ContNext for m_received being null

Make sure m_received is always null at ContSend, ContRaise,
and ContNext, and this information to generate better code for these
bytecode instructions.
Fix defaults for preg ini settings

Use the RuntimeOptions, rather than hard-coding them
New Block invariant

It's a little hard to reason about how lastMarker works in
codegen wrt blocks that don't have Marker.  In a optimization pass for
hoisting CheckType instructions I'm running into cases where I'd have
to track arbitrarily far backward in the main trace to find a Marker
that needs to go into the exit trace; it seemed simpler to just always
have a Marker in the front of each block.
Hoist CheckType instructions above generic IncRef/LdMem @override-unit-failures

Because we normally find out about a type prediction at hhbc
bounderies, sometimes we generate type checks after we've already done
some generic operations on Cells.  This optimizes a specific pattern
of this that occurs in vector translations.  The code is set up as if
there is more than one since I have another case partially
implemented, but it currently hits issues in both linearscan and
codegen that need to be addressed first, so I split the diff for now.
Revert "HphpArray"
expose Vector->count() for use inside hphp