PoC asset loading plugin

[CedricGuillemet]

This is a Proof of concept for plugins and more particularly asset loading/http requests.
Remarks/critics/ideas/... hugely welcome. I guess you have a better/more clear view of the plugin architecture :)

I added a Plugins folder at the root. Then 1 subfolder per plugin.
Console is a simple example.

#include <Console/Console.h>

then

runtime->Dispatch([](Babylon::Env& env)
        {
            Babylon::Console::CreateInstance(env, [](const char* message, auto)
            {
                OutputDebugStringA(message);
            });
        });

Things get more complicated with HTTP requests:

• There might be some CPP involved. Do we create a plugin CMake to make a library or let Apps do it?
• XMLHttpRequest has a depedency on Arcana. How can we avoid it?
• Is there a better place in the directory tree for these files ?

An example of use on Android is:

#include <XMLHttpRequest/Android/XMLHttpRequestAndroid.h>

then in the App:

runtime->Dispatch([](Babylon::Env& env)
        {
            Babylon::XMLHttpRequestAndroid::CreateInstance(env, asset_manager);
        });

It doesn't build, don't even try.

[CedricGuillemet]

@bghgary @syntheticmagus

I did some changes and got some issues I need help with.

Changes:

• PluginHost interface as RuntimeImpl is not accessible from the outside. I think the name is selfexplicit https://github.com/BabylonJS/BabylonNative/pull/130/files#diff-c6bfa4c2e51a9f3aa875a6237c8234baR1
• Loading JS using JS https://github.com/BabylonJS/BabylonNative/pull/130/files#diff-91affc66b12cbf8cc748309b61bca936R82 To do the full loop, I need to use JS for loading so the plugin is properly called
• plugin folder and Console and HTTPRequest plugins

Issues:

• I get a crash when calling eventHandlerRef.Call({}); from SetReadyState. I don't know yet why it's failing

[bghgary]

Ideally, don't call WideCharToMultiByte twice if both length and buffer are specified.

[CedricGuillemet]

Closing PR