Add overlay and multiply effects to gdImageSetPixel
add tests for layer effects
Fix buffer overrun from long font search path

MAXPATHLEN is set to 256 (on some systems), and DEFAULT_FONTPATH is longer
than this (on some systems). The sprintf() to path[MAXPATHLEN] thus
resulted in a buffer overrun when in some circumstances (also,
fontsearchpath is in the control of the environment, so this could be
triggered on any platform).
CVE-2014-2497, NULL pointer dereference, fix #126
Merged in ttoohey/gd-libgd/bugfix/font_path_overrun (pull request #19)

Fix buffer overrun from long font search path
Merged in ttoohey/gd-libgd/layout-effect (pull request #18)

Overlay and multiply effects for gdImageSetPixel
Restore support for alphaBlendingFlag value gdEffectAlphaBlend
Merged in nathanaeljones/gd-libgd/nathanaeljones/restore-support-for-alphablendingflag-va-1409782287517 (pull request #20)

Restore support for alphaBlendingFlag value gdEffectAlphaBlend
bootstrap.sh now offers build tips on OS X and defaults to glibtoolize
Add gdTestAssertMsg(condition, formatmessage, variables) to support detailed failure messages.
Improve error reporting and diagnostics in gdimagefile test.
Fix 'max' definition conflict on some compilers.
Silence automake 1.14 warnings ("source file is in a subdirectory, but option subdir-objects is disabled").
Add libiconv support to CMake files
Support MSVC++ 2013 and higher: define _ALLOW_KEYWORD_MACROS, inline, strcasecmp, snprintf.
Merged in nathanaeljones/gd-libgd/msvc-fix-keyword-macros (pull request #25)

Support MSVC++ 2013 and higher: define _ALLOW_KEYWORD_MACROS, inline, strcasecmp, snprintf.
Merged in nathanaeljones/gd-libgd/cmake-iconv (pull request #24)

Add libiconv support to CMake files
Merged in nathanaeljones/gd-libgd/shut-up-automake (pull request #23) Silence automake 1.14 warnings

Silence automake 1.14 warnings ("source file is in a subdirectory, but option subdir-objects is disabled").
Merged in nathanaeljones/gd-libgd/add-osx-boostrap-support (pull request #21) - bootstrap.sh now offers build tips on OS X and defaults to glibtoolize

bootstrap.sh now offers build tips on OS X and defaults to glibtoolize
Merged in nathanaeljones/gd-libgd/test-message-improvements (pull request #22)

Add gdTestAssertMsg(condition, formatmessage, variables) to support detailed failure messages.
Improve error reporting and diagnostics in gdimagefile test.
Fix 'max' definition conflict on some compilers.

Add gdTestAssertMsg(condition, formatmessage, variables) to support detailed failure messages.
Fix possible buffer read overflow
detected by -fsanitize=address, thanks to Jan Bee
move overflow test outside the loop for perf