Automerge feature. (#313)

Add the `automerge` attribute to the Pixel bit field. It controls
whether two pixels must be automerged. Defining this allows two
mergeable characters not to be merged.

This was requested by:
https://github.com/ArthurSonzogni/FTXUI/issues/285

CHANGELOG.md

@@ -6,6 +6,10 @@ unreleased (development)
 
 ### Features:
 
+#### Screen
+- Add the `automerge` to the Pixel bit field. This now controls which pixels are
+  automatically merged.
+
 #### DOM:
 - Add the `Canvas` class and `ElementFrom('canvas')` function. Together users of
   the library can draw using braille and block characters.
@@ -30,6 +34,9 @@ unreleased (development)
 
 ### Bug
 
+#### Table
+- The `table` horizontal and vertical separator are now correctly expanded.
+
 #### Component 
 - `Input` shouldn't take focus when hovered by the mouse.
 - Modifying `Input`'s during on_enter/on_change event is now working correctly.