Similar to grep or test, 1 is reserved for "no", 2 is used for
"incorrect use/syntax"

Allow usage_is caller specify exit status or suppress exit completely

Fastfoo libraries are not intended for interactive sessions (use *fff*),
we are only enabling this to aid development and testing process.

This uses even other function __cut_stack to identify two function
names: $caller is the first function on the stack to be be outside
API and is interesting for user so can be used in pretty printer
(typically for debug output).  $internal is name of the wrapper
from this API; this is used to choose the right pretty printer
(debug, warn...).

Make it clear that the assignment must happen, otherwise we might easily
end up wit empty src or mixup between local and caller's local.

Things have grown and some parts of layout now make more sense being in different module

Mkpretty is now always on and defined globally as name of the pretifier,
which is "plain" by default.

"plain" prettifier only adds "debug" and caller name prefix to the debug
output.

usage is supposed to be implemented in user script by call to usage_is
(so that the actual patterns can be defined only once and on the lowest
indent level).

So actually when we see usage_is, we want to skip one FUNCNAME in stack.
(This will not work properly if the suggested usage is not adhered to.)

Use common backend, add -f and -c, add arbitrary pretty printers support

Do not rely on IFS; it does not work with quotes, i.e. spaces in paths.

iniread will now read either specified files or try to find them in
FFOOD_INIPATH, which is empty by default

All other files have been moved to *eecc* and whole qecc
history (~300 commits) has been squashed into this commit.