aurbot[3547325]: [CRITICAL] name 'fp' is not defined
aurbot[3547325]: [ERROR] Unknown error. Please report it with --debug.

- Move maintainer check in update. So, no more maintainer check if there is
no need to build the update
- Move build code in a subfunction
- Improve some messages

Prevent later failure with invalid path in tarball

Since python 3.5 we need to raise an exception to prevent python to EINTR
see https://www.python.org/dev/peps/pep-0475/

Drop python-xdg deps

This replace global sleep time of the daemon

Build and commit command/duration was printed at the end of the log instead
of the time they are available

- Takes config object
- Display build and commit duration
- Improve error reporting

- New "cache" system, using persistant data dir
- Change argv options (remove --cache-path)