libbase/ab{die,warn,err,info,...}: Use BASH_SOURCE & BASH_LINENO in err msgs

[Artoria2e5]

Expected output:

[WARN] foo/bar.sh:233: blah.

Extra points for abdie: backtrace.

Crappy things:

• . will introduce an extra level of func call.
  • recsr gives you two, but that is acceptable.

Alternative solutions:

_abdie(){ ...:$errline: }
alias abdie='errline=$LINENO _abdie'

This will result in some by-func-or-by-script addressing. When you get source from FUNCNAME[0], you should look at BASH_SOURCE instead.