Add gcc-8 to Travis.

Fix project opening while filter is applied.

C#: Throw ObjectDisposedException from disposed wrapper classes

C#: Add random functions to GD class

Fixes #25268

Fix warnings seen with warnings=all and recent GCC 8.2.

Allowing setting particles lifetime greater than 600

C#: fix Quat.Equals.

Fixed area collision report with concave

Add hex-encoded version number to Engine singleton for easy comparisons

Make direct casting among Error and godot_error enums (#23015).

Added shadow_color property to gles2

Added support to scale areas, fixes #23448

Auto-cleanup missing addons

Fix description size in "New Node" dialog

Fix AudioStreams::stop possibly causing a small noise

Small improvements to the Resource doc