Each Enter or Backspace key press will repeat several times in GLFW.

I'm using GLFW 3.3 with GL3 backend under MacOS v10.15.1.

In TextEditor, each Enter or Backspace key press will generate several key press events which makes the TextEditor nearly unusable.

I compiled nuklear with below defines:

```
NK_INCLUDE_FIXED_TYPES: 1
NK_INCLUDE_STANDARD_IO: 1
NK_INCLUDE_DEFAULT_ALLOCATOR: 1
NK_INCLUDE_VERTEX_BUFFER_OUTPUT: 1
NK_INCLUDE_FONT_BAKING: 1
NK_INCLUDE_DEFAULT_FONT: 1
NK_KEYSTATE_BASED_INPUT: 1
```

How to fix it?

Reproduce the issue in the GLFW 3.3 GL3 backend on macOS 10.15.1 using the TextEditor and the listed Nuklear defines. Inspect the keyboard event and TextEditor input paths to determine why Enter and Backspace repeat; done means each physical key press produces one corresponding editor action.

Written by the indexing model from the issue text.