Unused.

To block template argument deduction.

The first three based on range-v3.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1651

Exposed by:

$ make CPPFLAGS=-O0

It was only used for C++<11 which does not allow default parameters
in function templates.  Looks like we cannot support <11 anyway, so,
start cleaning up.

We'll see if bots like.

That's a C++11 extension apparently...

Removes use of auto type deduction again, which was not supported on many bots.

Sorry for the noise, downstream custom builders.  Please adjust.

Move it to new harfbuzz-gobject library.  Implement enums and
boxed types for object-types.  Still have to do boxed types for
value types.

Initial setup of gtk-doc. Straight forward setup following the gtk-doc
instructions. Ignore some troublesome types in src/hb-gobject.h. To
build use "./autogen.sh --enable-gtk-doc" then "make". Docs are in
harfbuzz/docs/reference/html/index.html.

Users should #include <hb.h> (or hb-ft.h, hb-glib.h, etc), but
never things like hb-shape.h directly.  This makes it easier to
refactor headers later on without breaking compatibility.