Made all header files to have LABWC_ prefix in include guard identifers.
Converted from __LABWC_ in 35 include/ files.
Converted from __LAB_ in 5 include/ files.
Added LABWC prefix to 3 include/ files.
Added include guards to 3 include/ files.
The double underscores were removed since according to C standard
those "are always reserved for any use".
This matches the behavior of the surrounding borders and will usually
cause resizing instead of triggering the button itself. This effect
is only really visible when using a border width settings of > 1.
Fixes#379
Support returning the following structs:
- view from LAB_NODE_DESC_VIEW or LAB_NODE_DESC_XDG_POPUP
- lab_layer_surface form LAB_NODE_DESC_LAYER_SURFACE
- lab_layer_popup from LAB_NODE_DESC_LAYER_POPUP