fix wrong Row number in DiscoveryDialog.py that caused following traceback:

Traceback (most recent call last):
File "/home/beremiz/beremiz/ProjectController.py", line 1536, in _Connect
dialog = DiscoveryDialog(self.AppFrame)
File "/home/beremiz/beremiz/dialogs/DiscoveryDialog.py", line 124, in __init__
self._init_ctrls(parent)
File "/home/beremiz/beremiz/dialogs/DiscoveryDialog.py", line 121, in _init_ctrls
self._init_sizers()
File "/home/beremiz/beremiz/dialogs/DiscoveryDialog.py", line 73, in _init_sizers
self._init_coll_ButtonGridSizer_Growables(self.ButtonGridSizer)
File "/home/beremiz/beremiz/dialogs/DiscoveryDialog.py", line 64, in _init_coll_ButtonGridSizer_Growables
parent.AddGrowableRow(1)
File "/usr/lib/python2.7/dist-packages/wx-3.0-gtk2/wx/_core.py", line 15343, in AddGrowableRow
return _core_.FlexGridSizer_AddGrowableRow(*args, **kwargs)
PyAssertionError: C++ assertion "!m_rows || idx < (size_t)m_rows" failed at ../src/common/sizer.cpp(1967) in AddGrowableRow(): invalid row index

Beremiz installation 
====================

Windows
-------
Download installer, install. 

Linux
-----
Pre-requisites::

    # Ubuntu/Debian :
    sudo apt-get install python-wxgtk2.8 pyro mercurial
    sudo apt-get install build-essential bison flex python-numpy python-nevow

Prepare::

    mkdir ~/Beremiz
    cd ~/Beremiz

Get Source Code::

    cd ~/Beremiz
    
    hg clone http://dev.automforge.net/beremiz
    hg clone http://dev.automforge.net/plcopeneditor
    hg clone http://dev.automforge.net/matiec

Build MatIEC compiler::

    cd ~/Beremiz/matiec
    ./configure
    make

Build CanFestival (optional):: 

    # Only needed for CANopen support. Please read CanFestival 
    # manual to choose CAN interface other than 'virtual'::

    cd ~/Beremiz
    hg clone http://dev.automforge.net/CanFestival-3
    
    cd ~/Beremiz/CanFestival-3
    ./configure --can=virtual
    make

Launch Beremiz::

    cd ~/Beremiz/beremiz
    python Beremiz.py