ffi: Cleanup.
ffi: Update tests for latest API.
Add test for accessing variables (errno).
Rename API sqrat_import() to sq_import().
sqimport: Keep reference to module name object while we use it.
Pulled error printing changes from squirrel-lang.
sqimport: Module loading debugging support.
Automatically import module "stdlibinit" on startup.

This module is supposed to import other import stdlib functionality, like
high-level import. If import fails, issue warning.
Move interpreter files to a separate dir after all.
Add minimal stdlibinit.nut module (bootstraps high-level import support).
Add install target for modules' Makefiles.

Installs in ~/.squirrel/lib/.
Install binaries too (to ~/bin). This includes rlwrap wrapper script.
Add top-level Makefile.

Run "make" to build everything, the "make install" to install everything
under your home dir.
import: Handle roottable hacks in modules properly.

Instead of passing in empty namespace table, pass clone of roottable
to module, while setting this clone as roottable too. Then restore original
roottable.

XXX: This is of course not too memory-efficient, disallow roottable hacks
in modules?
Revert "import: Handle roottable hacks in modules properly."

This reverts commit 0ec88864f6a2ccc1dc3583882286a14b29ceb568.

Just disallow roottable hacks in modules. To assign to module environment,
use module-level "this".
Add initial development on "os" module (via FFI).

TODO: Consider naming better.