Minor clean-up to quick_tests.sh.

- Reformat line.
- Fix typo.
- Remove unused comment.
- Reformat comment.
Fix: `test.sh` did not run if called from within `test` directory.

Solution: Get directory name from script's path, as it is done by the
other scripts.
Minor clean-up to test.sh.

- Reformat for-loop to not be squeezed into a single line.
- Use `$(...)` instead of old-style backquote for command substitution.
- Remove outdated comment.
Clean-up: No need to manipulate the path, shinken_test does this already.
Cleanup imports.

- Replace `from ... import *` by concrete names.
- Remove unused imports (sys, shinken).
Add helper module for importing the shinken library from parent dir.

I put this into a separate module as it may be useful for test-cases not
importing `shinken_test` for any reason.
Remove pseudo-compatibility function shinken.utils.if_else().

This function was introduced in
2012-05-01T21:44:00Z!gerhard.lausser@consol.de as "a ternary operator
workaround ensures compatibility with python 2.4".

Using a function has a major drawback: all values passed as arguments have
to be evaluated prior to the call. In opposite to the ternity operator and
the well-known `... and ... or` pattern, where only the resulting part gets
evaluated.

It is used only in shinken.log and one of the values passed is
`time.asctime(time.localtime(time.time()))` which is quite heavy for being
evaluated without using it.

So I remove this function at all and replace it by either boring if-else-
statements or the `... and ... or` pattern.
Clean-up: Use time.asctime() w/o parameters if `now` is meant.

time.asctime defaults to `now` if no parameter is given. So there is no
need to pass somwthing like time.localtime(time.time()).
Fix: logging level must be set when instantiating the Log object.

A Log object need a logging level attribute even if load_obj() is not
called (and thus no broker for collecting the log messages is attached).
Allow turning of the human timestamp format after it's been turned on.

The interface of logging.Log did only allow to switch to the human timstamp
format, but not switching back. This will be rarely used in applications
but is needed for test-cases.
Add a test-suite for testing the `shinken.log` module.
Add doc-strings and more meaningful comments.
Activate already implemented test-case (by removing leading underscore).

I can't remember why this was deactivated. Probably it I was unsure
it'll work when I implemented the test-suite.
Fix test-case for human timestamp format and local logging.

As of now, the local log gets prefixed another timestamp. But it is
yet unclear, whether this intended or not (see
<http://sourceforge.net/mailarchive/message.php?msg_id=29553475>). So
I decided to adopt the test-case to the code until somebody steps
forward to decide on the format.
Add test_logging.py to quick_tests.
Merge branch 'feature/cleanup-logging'.
Remove superfluous import of shinken.objects in shinken/_init__.py.

Every script or test-case importing shinken has all the objects loaded,
even if they are not required by the script or test-case at all.

Also see <http://sourceforge.net/mailarchive/message.php?msg_id=29553474>.
Merge pull request #485 from htgoebel/master

Test-suite for shinken.logging and some clean-ups.