Meson support upgrade to version 0.52.0.

Adding basic ignore entry for example and main build directories.

Adding Meson build script into hit attributes as text.

This is because Meson now has better support for static libraries.

Update CMakeLists.txt minimum version

Update the CMAKE minimum version from `3` to `3.0` to fix error in Windows 10 x64 with CMAKE 3.15.4:

cmake_minimum_required could not parse VERSION "3".

Fix "rake scripts" when running on Windows.

Fix Meson build system support.

Update CMake support.

Fix malloc alignment (Thanks @alecoding )

Fix compiler complaint about declaration after statement

The realloc was not taking in account extra bytes needed for the the pointer proper alignment

Make sure the malloc alignment is always aligned to the architecture's pointer size

Fixed a simple mistake.

Removed Unity version number from Meson build scripts so there is one less thing to change when doing updates to this script.

Added new CMakeLists.txt here in the src dir, moved add library method from root script to sub script.

Moved the add library method into sub dir.  Also made this CMakeLists.txt script compatible for versions os CMake starting from 3.x and up.

Put source in an array, cleaned up script and fixed comment.

Removed newlines and fixed comment.

Added foreach loop to avoid DRY, Put source files in map structors, fixed comment.

Moved example dir variable into source meson.build script, fixed comment.

Removed 'unity_src' variable because Unity only one source file, changed library method to static only because there was some issues with using Unity as a shared library, cleaned sub meson.build script and fixed comment in sub source root.

Cleaned up compiler flags in root meson.build, renamed a variable and removed 'c_std=<standard version>' because Meson sets C standard flag to C11 by default.

cmd.exe does not recognize backslash as an escape character,
leading to errors like the following:

    error: stray '\' in program
    note: in definition of macro 'UNITY_OUTPUT_CHAR_HEADER_DECLARATION'

It does, however, recognize double quotes, so we can use those as
a portable method of escaping special characters on both Windows
and UNIX.

Get the 2's compliment of the unsigned int `number` when printing results without relying on problematic recasting of a negated int. (see #439)

optimisation(AVR): Store static string in AVR EEPROM

* This can save a lot of program memory and allow to run test on ATTiny

Quick fix to Meson example.

Add TEST_MESSAGE for outputting messages without aborting a test and _MESSAGE variant to TEST_PASS collection.