remove unused code

Reviewed By: @alexmalyshev

Differential Revision: D1090454
Loosen refcount verifier on DefLabels

Sometimes we end up with a DefLabel that defines a value with type
Cell, but only has one incoming value with an uncounted type. The Cell dest of
the label won't have any tracked references since it's always uncounted, so
recognize that situation and don't abort.

Reviewed By: @ptarjan

Differential Revision: D1090701
Use std::atomic<> in TreadHashMap

Convert TreadHashMap from atomic_{acquire_load,release_store} to
std::atomic<>.{load,store}.

Reviewed By: @jdelong

Differential Revision: D1084196
Use std::atomic<> for condition flags

Convert atomic_acquire_load and __sync_fetch_and_{and,or} on condition
flags to std::atomic<>.{load,fetch{and,or}}.

Reviewed By: @jdelong

Differential Revision: D1084266
Fix up the const-to-variant code

Several cases were doing it wrong.  Found them while auditing
implicit Variant constructors.

Reviewed By: @jdelong

Differential Revision: D1077928
Add the Reflection class

We never defined the actual Reflection class, which just has two
static methods in it.

Appeases yii, which has a requirements check that determines whether
the Reflection extension is enabled by searching for this class.

Reviewed By: @ptarjan

Differential Revision: D1086615
fix more vfprintf

Reviewed By: @JoelMarcey

Differential Revision: D1091125
Implement GlobIterator

Required changing the behavior of DirectoryIterator and
FilesystemIterator. DirectoryIterator should iterate through the base
names of files, but FilesystemIterator iterates through full
pathnames.

Fix a bug in RecursiveIteratorIterator along the way

Reviewed By: @ptarjan

Differential Revision: D1034196
fix afile

Reviewed By: @andralex

Differential Revision: D1091032
make rename_variation parallelizaable

Reviewed By: @JoelMarcey

Differential Revision: D1091010