Fix error about missing attribute 'timeout' that happens sometimes during compilation

The fix [1476:49f1763a5613] of the problem with following trace was wrong.
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'
The problem was that compilation process was finished before the timeout attribute is set.
Now timeout is set before launcing of compilation process.

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.