- display the output of all commands launched by erp5testnode in
  erp5testnode log
- add a thread to upload ongoing logs to the master regularly
- if the software release is not built successfully after a
  few time, totally erase software. This help unblocking if
  buildout is unable to update software.
- check if the last test result was cancelled in order to
  allow relaunching test without restarting testnode
- improve logs to allow much better understanding of what is
  going on