After this commit alone it would not work when installed (unless module
paths are set in a special way). Next changes will introduce
installation to site-packages so no custom PYTHONPATH will be necessary.
For convenience (seemingly, and it really is convenient) equo and other
tools can be run from the checkout, and Entropy modules are loaded from
the checkout. Now there is a strict separation when system paths and
when paths from the checkout are used.
It makes it a bit more robust, secure and preditable at the cost of
a little more complexity.
A pleasant side effect of this change is that it is not required to
change directory to the tool (to use non-system one), as paths in the
checkout are relative to scripts.
Imports in lib/tests were not adjusted.
