Add New InputSystem Compatibility

[vmichalak]

I've add a support for the new input system without breaking the old one.

[vmichalak]

This MR solve issue #31

[yasirkula]

I have a couple of trivial changes to your latest commit in my mind but the most important thing right now is this:

We must test if this breaks compatibility with Unity versions 2017.3 to 2018.2 where Assembly Definition Files exist but apparently, new Input System doesn't.

I'll give it a shot soon.

[yasirkula]

I'm sorry for the delay. This PR is still in my to-do list but I've been busy with work. Just wanted to let you know.

[vmichalak]

No Problem @yasirkula, I only did this PR because I corrected the lib for me. Take the time you need.

[yasirkula]

So today I've made some research about the new Input System:

• It appears that EventSystem now requires a Input System UI Input Module component. If the scene doesn't have an EventSystem object, then IngameDebugConsole prefab's EventSystem will be used and it doesn't have this component by default. This requires manual modification by the user
• ENABLE_LEGACY_INPUT_MANAGER and ENABLE_INPUT_SYSTEM compiler directives are only available on 2019.2.6 or newer. This makes these compiler directives useless for me. We can't determine which input system(s) are active without using reflection. This ultimately requires manually entering a compiler directive to IngameDebugConsole.Runtime assembly's Version Defines list (also note that Version Defines isn't available on older Unity versions)
• On Unity 2019.1+, it is possible to have Assembly Definition References to packages that are not present in the project but on older Unity versions, this will result in compiler errors. This requires either manually adding the Unity.InputSystem package to IngameDebugConsole.Runtime assembly, or manually removing it on 2018.4 or older

As you can see, there are a lot of manual changes needed just to be able to access new Input System from scripts. Manual changes also means that asset mustn't be installed through Package Manager because package source codes aren't included in version control system and thus, the changes won't persist on version control or when Library folder is deleted (e.g. cloning the project).

All these negative points strongly discouraged me from adding support for new Input System. I may revisit this issue later.

[HyVong007]

My temporary solution is using both old input system (UnityEngine.Input) and new Input System in my project. But i wish that you will use InputSystem very soon.

[yasirkula]

Issue addressed in https://github.com/yasirkula/UnityIngameDebugConsole/commit/6123ac72027a0cc2355465562ce598b96079351c