allow generating most cdefs for lua
Motivation: maintaining these by hand in kres.lua is tricky, as just
inserting or reordering the structures can do anything and isn't
detected in general. For example,
rr_array_t::at has always
"missed a star".
A couple libknot structure fields have apparently changed name since the old definitions were written; in most cases I renamed them in *.lua.
The file daemon/lua/kres-gen.lua will be regenerated only if explicitly deleted. That requires building with debug symbols and gdb on $PATH.