fixes sometimes happened error during project compilation

Traceback (most recent call last):
File "./Beremiz.py", line 1229, in run_with_except_hook
run_old(*args, **kw)
File
"/home/developer/WorkData/PLC/beremiz/beremiz/util/ProcessLogger.py",
line 68, in run
self.endcallback(self.Proc.pid, err)
File
"/home/developer/WorkData/PLC/beremiz/beremiz/util/ProcessLogger.py",
line 169, in finish
if self.timeout: self.timeout.cancel()
AttributeError: ProcessLogger instance has no attribute 'timeout'

Project overview
================

In order to target the widest possible range of programmable devices and keep efficient, Beremiz use C code as an intermediate language. 

To be executed, C needs to be compiled. `GCC <http://gcc.gnu.org>`_ serve that purpose perfectly.

PLC program is expressed in languages defined in IEC-61131, including graphical languages. Thanks to PLCopen TC2, those graphical languages have a standardised representation, in XML.

To be continued.