This results in less merge conflicts when using the
Text Editor > Files > Trim Trailing Whitespace editor setting.
.ptex, .mmg and .json files generated weren't modified
as these are saved by Material Maker. These files could be made
to end with a newline automatically on save in a future commit.
`.import` files (not to be confused with the `.import/` directory)
should be included in version control as they contain important
metadata, such as whether a texture should be filtered or not.
A `.gdignore` file was added to the `doc/` folder of the add-on,
which prevents Godot from importing any files inside.
This also speeds up the initial editor import step.
Added documentation for Material, Export, Comment, Switch and Remote nodes.
Fixed missing "tool" attribute in editable_label script.
Reordered misc. nodes in base library.
