Add documentations for HEIF specifications. Include reference to all materials about HEIF.

Hello,

Did you abandon this project?

Let's start to define JavaScript API for the module.

In HEIF Wiki is explained how to compile using MinGW Toolchain but it could be better to compile throgh Visual Studio Toolchain so investigate this possibilities.
See:
https://blogs.msdn.microsoft.com/vcblog/2016/10/05/cmake-support-in-visual-studio/
https://github.com/nokiatech/heif/wiki/I.-How-to-build-HEIF-Source-Code

Add HEIF C++ API library as submodule in the repo. The HEIF repo is reported below:
https://github.com/nokiatech/heif.git

It is important in some circumstances take decision based on different version of the underlying library. Heif will expose the information about the C++ heif library. Below I report the API

//Property that represents the version of the library. It will be a string  
Heif.VERSION 
//Property that represents the major version of the library. It will be a number  
Heif.MAJOR 
//Property that represents the minor version of the library. It will be a number
Heif.MINOR 
//Property that represents the minor minor or patch version of the library. It will be a number
Heif.PATCH 
//Property that represents the code name of the library. It will be a number
Heif.CODE_NAME 

This API has the responsibility to read the configuration file as specified by the standard https://github.com/nokiatech/heif/wiki/II.-HEIF-Writer-Library-and-Configuration-Examples#heif-json-configuration-format and create the heif file. I think that in this first version of the module we can create the file as specified path and / or return the stream of it.

This API has the responsibility to read the configuration file as specified by the standard https://github.com/nokiatech/heif/wiki/II.-HEIF-Writer-Library-and-Configuration-Examples#heif-json-configuration-format and give us the access to all the components of the heif file like reported in the following example:
https://github.com/nokiatech/heif/wiki/III.-HEIF-Reader-API-and-Usage-Examples
There is a JS implementation but I prefer to reimplement the API on this addon to get better performance and not just an adapter to the pre-existent module.

Try to compile the HEIF C++ library on macOS and use it local to node native addons.

Try to compile the HEIF C++ library on Linux and use it local to node native addons.