selog-8.7.30 - selective logging library

I have released a new version of selog. The only significant change is C++ support, requested by filecoreinuse.

One thing I would like to be able to do in C++ is call a selector, so that sel(fmt, ...) works like selog(sel, fmt, ...). (The Lua API supports something like this.) However as far as I can tell this would require variadic templates to implement efficiently (i.e. to inline the selog_on() check) and this is probably reaching too far into voodoo territory to be sensible.