VeNum optimizations to libpng to improve PNG decode time

Set correct counter in neon routine for SUB filter type.
Enable Neon optimizations for all filter types and pixel depths.
cherry picked from commit b912f64bc4bb174fc055cda58e303faaa640b8b1

Change-Id: I4ff1c78637db1ab91689ad90da9b5e7da07d2a9e
Update copyright to The Linux Foundation

Change-Id: I537e53b3bb9145aabb60dc482c495118d1f06b03
libpng: Fix for memory leak while indexing the PNG images

de-allocating the index resorces at proper place. png_read_destroy()
making png_ptr->index NULL and due to this de-allocation was not
happening even though code exist (it was like dead-code).

Change-Id: I770bbfc486365b1a8b6a8dc5f128aa2b3a34cd50
CRs-Fixed: 551617
libpng: Squashed update to version 1.2.51

[legacy] Updated ANNOUNCE

[legacy] Bump version to libpng-1.2.47beta01

[legacy] Updated contrib/pngminus/makefile.std

[legacy] Reverted non-portable GNU syntax in makefile (?=, +=)

[legacy] Deleted some extra blank lines from visualc6 and 71 README files.

[libpng12] Imported from libpng-1.2.47rc01.tar

[libpng12] Imported from libpng-1.2.47.tar

[libpng12] Bump version to 1.2.48beta01

[libpng12] Removed two useless #ifdef directives from pngread.c and

one from pngrutil.c

[libpng12] Eliminated redundant png_push_read_tEXt|zTXt|iTXt|unknown code from

    pngpread.c and use the sequential png_handle_tEXt, etc., in pngrutil.c;
    now that png_ptr->buffer is inaccessible to applications, the special
    handling is no longer useful.

[libpng12] Fixed bug with png_handle_hIST with odd chunk length (Frank Busse).

[libpng12] Fixed off-by-one bug in png_handle_sCAL() when using fixed point

arithmetic, causing out-of-bounds read in png_set_sCAL() because of failure
to copy the string terminators (Franke Busse).

[libpng12] Imported from libpng-1.2.48beta01.tar

[libpng12] Bump version to 1.2.48beta02

[libpng12] Removed png_free() of unused png_ptr->current_text from pngread.c.

[libpng12] Added libpng license text to pnggccrd.c and pngvcrd.c

(requested by Chrome).

[libpng12] Imported from libpng-1.2.48rc02.tar

[libpng12] Update ANNOUNCE about pnggccrd.c change

[libpng12] Fixed date in ANNOUNCE.

[libpng12] Imported from libpng-1.2.48.tar

[libpng12] Update version numbers in ANNOUNCE

[libpng12] Imported from libpng-1.2.49.tar

[libpng12] Imported from libpng-1.2.50.tar

[libpng12] Ignore, with a warning, out-of-range value of num_trans

in png_set_tRNS().

[libpng12] Update copyright year in recently-changed files

[libpng12] Bump version to 1.2.51beta01

[libpng12] Changed AM_CONFIG_HEADER(config.h) to AC_CONFIG_HEADERS([config.h])

in configure.ac

[libpng12] Changed default value of PNG_USER_CACHE_MAX from 0 to 32767

in pngconf.h.

[libpng12] Imported from libpng-1.2.51beta01.tar

[libpng12] Bump version to 1.2.51beta02

[libpng12] Avoid a possible memory leak in contrib/gregbook/readpng.c

[libpng12] Update GIT URL in the manual.

[libpng12] Updated README description of contrib and projects directories

[libpng12] Imported from libpng-1.2.51beta02.tar

[libpng12] Bump version to 1.2.51beta03

[libpng12] Fix spelling of "doclifter" in CHANGES and ANNOUNCE

[libpng12] Changed '"%s"m' to '"%s" m' in png_debug macros to improve

portability among compilers.

[libpng12] Updated copyright year in recently-changed files.

[libpng12] Rebuilt configure scripts with autoconf-2.69 and automake-1.14.1

[libpng12] Updated copyright year in png.c.

[libpng12] Imported from libpng-1.2.51beta03.tar

[libpng12] Bump version to 1.2.51beta04

[libpng12] Removed potentially misleading warning from png_check_IHDR().

[libpng12] Imported from libpng-1.2.51beta04.tar

[libpng12] Bump version to 1.2.51beta05

[libpng12] Quiet set-but-not-used warnings in pngset.c

[libpng12] Imported from libpng-1.2.51beta05.tar

[libpng12] Imported from libpng-1.2.51rc01.tar

[libpng12] Quiet an uninitialized memory warning from VC2013 in png_get_png().

[libpng12] Imported from libpng-1.2.51rc02.tar

[libpng12] Quiet unused variable warnings from clang by porting PNG_UNUSED()

from libpng-1.4.6.

[libpng12] Imported from libpng-1.2.51rc03.tar

[libpng12] Removed a stray semicolon after PNG_UNUSED(params) in pngread.c

[libpng12] Update "last changed" info in source files.

[libpng12] Added "-D_SOLO" to contrib/pngminim makefiles (for zlib-1.2.6+)

[libpng12] Imported from libpng-1.2.51rc04.tar

[libpng12] Added an #ifdef PNG_FIXED_POINT_SUPPORTED/#endif in pngset.c

[libpng12] Imported from libpng-1.2.51.tar

Change-Id: Ia89e7d1e5c17a1c1b179d0b805ba5427d5d54ca2