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".
Adds two new theme vars:
- menu.width.min (menu will never be smaller than this)
- menu.width.max (menu will never be wider than this + padding)
A fixed menu width can be achieved by setting
menu.width.min == menu.width.max.
IMHO it encourages better design (by making dependencies more obvious)
to have source file/header file pairs like view.c/view.h, rather than a
monolithic header like labwc.h with everything in it.
I don't think we need to break up all of labwc.h at once, but maybe we
can start pulling it apart bit by bit as it's convenient.
Also:
- Move "struct border" to ssd.h so that view.h can use it without pulling
in all of labwc.h.
- Add a missing required #include within scaled_font_buffer.h (forward
declaration of "struct font" is not enough).
