Support test folder structure where test, oracle and generated result
data are stored each in separate directory.  This makes it easier to
ensure legible diff output without cluttering the filenames too much.

Apparently leftover from earlier TF version.

They can be any executables now.

This was obviously a bug.

Previously the framework was silent in cases such as when enumeration
fails (maybe due to enum functions not implemented), returns nothing,
or if regex in TF_FILTER_SUBTEST leaves nothing.

Now it bails out on errorneous or empty enumeration, and adds debug
message if TF_FILTER_SUBTEST is "too hungry".

Also, intermediary lists are saved to file and left for artifact
collection.

Most changes are in tf_do_subtest.

 *   Separated setup/cleanup logic from test data collecting and
     execution/evaluation.

 *   Revamped the execution/evaluation logic in a new tool testflt,
     allowing tester to use it as the need be.

 *   Code to compose actual test command removed, as testflt makes it
     easy to write the code in one place (TF_RUN) and keep simple things
     simple.

 *   Removed tf_parse_meta, as it's obsolered by above changes.

 *   Updated tests to reflect the new style.

(Thx Joe Spolsky for inspiration)

Apparently leftover from earlier changes, these files are exact
duplicates of their .oracle counterpart, but are not actually used by
local TF_RUN

...so that it can be understood by future reader.

Avoiding using the plain test name makes it easier to understand the
role of each file.

This as convention helps spot leaking variables and makes it
easier to document variables for reader

It is intended, documented and assumed in later code that any test must
contain this executable.

Make it

 *  more flexible,
 *  more readable,
 *  faster,
 *  take care of manpages (not fully done yet),
 *  take care of dist list,
 *  little bit more polished in various other things.

A more conventional hierarchy

This new hierarchy makes it easier to work simultaneously on data and
the script, simplifies deployment to tempdir and makes the launching
script naming consistent with simple.sh.

"doc" (not manpages) is built and installed with others.

Otherwise tests with --prefix break since they operate from independent
folder.

This should be consistent with `ffoom` and `ffdoc`