plugins.multiplexer: rename filter keywords

Rename them from filter_out and filter_only to filter-out and filter-only,
respectively.

Motivation: consistent with original RFC and easier to the eyes, specially when
new filter keywords get added (filter-depth, filter-value, etc).
examples: add a relatively complex multiplexer file

This is the tree we've been using in several of our discussions and
algorithm simulations.
avocado.job: fixing exception call on Ctrl+c

s/TestTimeoutError/TestInterruptedError/
Merge pull request #179 from adereis/mux

multiplexer misc commits
avocado.job: don't run additional tests if user hits Ctrl+C

Ctrl+C was aborting the current test, but avocado would keep
looping through the list provided in the command line.
Merge pull request #178 from adereis/ctrl_c_fixes

ctrl+c fixes
avocado.utils: Split download and url related libraries

To avoid a few oddities inside avocado code.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
avocado.utils.path: Add get_path API

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
avocado.utils.io: Add logging related functions

So we can introduce aexpect.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
avocado.utils.process: Add PID manipulation APIs

So that we can do things such as killing an entire
process tree, necessary for aexpect functionality.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
avocado.utils: Add wait library

Add a library for functions with the same pattern: wait for
another function to evaluate to True, for a certain amount
of time.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
avocado.utils: Add astring library

Add string manipulation APIs to the avocado.utils namespace.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
avocado.utils: Add aexpect library

Add aexpect, a near exact copy of the code that
has been used by virt-test for a long time. It
is a library for controlling interactive process,
similar to pexpect, but with some additional
properties:

* Programs may stay alive between tests and jobs
* More sophisticated class structure

Signed-off-by: Lucas Menghel Rodrigues
avocado.test: Set the base log dir for io.log_line on tests

So that when we use io.log_line, files get written to
the appropriate test log locations.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
avocado/utils/network.py: introduce unused ports related utilities

Signed-off-by: Cleber Rosa <crosa@redhat.com>
avocado.utils.params: Add copy() method
avocado.plugins.builtin: Fix plugin loading
Merge pull request #182 from lmr/virt-test-fixes

Virt test fixes
avocado: Introduce new, lean virt module

Mostly here to show you the results of my work with the
base code Stefan wrote for QEMU unittests. His code was
refactored and extended, to the point where basic boot
tests with real guests do work.

Next we're gonna show how the boot test looks like.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
tests/qemu: Add boot test

Example of a test made using the lean virt test module.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>