Add license information about wifi-ir-gateway

[viktak]

Hi there!
My code uses several other pieces of code (libraries) from other authors with varying licenses. I am not a legal expert, so I cannot assert what licensing form is permitted/suitable for my resulting work. I would love to use a license with very little restriction, but I cannot give you a license to use someone else's work.

I open sourced my code so that people can audit it, learn from it, etc.

If/when I will have the time I to do some research on this subject and I will include a license if it makes sense.

[vazhnov]

@viktak , then I suggest to start collecting information about third-party code here in this chat. After some time, maybe we will have full picture.

For example:

• src/NTP.h — Craig A. Lindley, license = unknown
• src/main.cpp — Viktor, license = ?

[viktak]

Licensing info added

[vazhnov]

Hmmm, CC BY-NC-SA 4.0 — strange but better than nothing. I don't like "NC" licenses :)
Thank you!