This is a very gentle commit that just lays the groundwork in the
build system: it puts the include files to build libtor-app.a into
src/core, and to build the tor executable into src/app.  The
executable is now "src/app/tor".

These might make it easier for people to link our stuff, and keep
their scripts more robust.

(Term is short for terminal)

We need to use lib/fs/winlib.h here so that we can use
GetTickCount64.

I would love to declare that XP is dead, and everybody has
GetTickCount64.

Note that procmon does *not* go here, since procmon needs to
integrate with the event loop.

Note that the workqueue code does *not* go here: it is logically at
a higher level, since it needs to use libevent and the networking
stack.

libtor-encoding is about various ways to transform data to and from
character sequences.

There are some additional changes to come: those points are marked
by XXXX.

The smartlist_core library now contains only the parts of smartlists
that are needed for the logging library.  This resolves the
circularity between "container" and "log".

The "containers" library still uses the logging code, and has the
higher-level smartlist functions.

This patch:
  - introduces an fdio module for low-level fd functions that don't
    need to log.
  - moves the responsibility for opening files outside of torlog.c,
    so it won't need to call tor_open_cloexec.

The locking code gets its own module, since it's more fundamental
than the higher-level locking code.

Extracting the logging code was the whole point here. :)

The other time stuff is higher-level

I am calling the crypto library "crypt_ops", since I want
higher-level crypto things to be separated from lower-level ones.
This library will hold only the low-level ones, once we have it
refactored.

Apparently it has no testing variant.

This change makes it possible for us to change the list of libraries
more easily, without changing every single linker line.

We had accumulated a bunch of cruft here.  Now let's only include
src and src/ext.  (exception: src/trunnel is autogenerated code, and
need to include src/trunnel.)

This commit will break the build hard.  The next commit will fix it.