Get rid of Business Template format version 0 as it's been deprecated for a while.
Reindent code following removal of Business Template format version 0.
ZODB Components: Remove useless useless safeguard 'exec' called before (re-)validating.

Pylint should be enough and has no side effects...
ZODB Components: If Pylint is not available, fallback on compile() builtin.

Likewise Pylint, compile() has no side effects as it juste compile source into
a code object which may be passed to 'exec'.
ZODB Components: Disable some pylint warnings.

Get rid of refactoring/convention/spurious messages (ERP5 Naming Convention
may be added later on). Also, Pylint cannot deal with dynamic accessor/module
generation, so disable these error messages as well.

Also, patch pylint to handle try/except for modules imports
(https://www.logilab.org/ticket/9386).
BusinessTemplate: Get rid of log warning due to a new ListBox parameter (ca3440e).
ZODB Components: Fix bt5 import from an archive.

The code wrongly assumed that the .py file (containing source code of a
Component) was on the filesystem upon import but importing from an archive
uses tarfile and does not extract anything...