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.
