ArrayInit constructor ssize_t -> size_t

In ArrayInit constructor, n is defined as ssize_t, but negative values
are not handled in any way. We should point that out to callers by
making n of type size_t.

Reviewed By: @edwinsmith

Differential Revision: D1017631
Fix ICU compliation when not using 51.x

'brew update' to a newer icu4c on OS X exposed that we aren't
being consistent in how we include it resulting in linker errors due to
confusion regarding what the icu namespace is.

Reviewed By: @sgolemon

Differential Revision: D1019529
Import php-src pull #479

Fix clowny error in zend-strtod.cpp on ARM platforms that passed through the PHP internals mailing list

Reviewed By: @JoelMarcey

Differential Revision: D1019758
Fix Buffer Overrun messages for tiff files

While processing tiff tags, the end pointer was not updated
after a realloc. Also, while processing IFD tag, end and begin pointers
were switched.

Closes #1154
Closes #1193

Reviewed By: @ptarjan

Differential Revision: D1019738

Pulled By: @scannell