Merged Mario's modbus fix : Modbus plugin: reset periodic activation timer when overrun occurs (delays due to communication errors, ...)

Modbus plugin: reset periodic activation timer when overrun occurs (delays due to communication errors, ...)

Disable MDNS:// scheme support. Also prevent discovery pannel to produce some. For now it seems that that feature is unused, and could be a security issue.

Added support to PYROS in Zeroconf discovery and publish. For now, PYRO://mdnsname._tcp.local. URI are broken, and discovery panel generate IP based URI by default.

PyroServer: fixed naming of class, and reorganized methods in order to ease subclassing, in case of customization of service publication on the local network (i.e. zeroconf)

Fix exception dialog with non recognized URI schemes

Fixed runtime's reconnecting loop not stopping when re-configuring WAMP.
In case WAMP was already trying to connect without success and user change WAMP configuration through web interface, previous ReconnectingClient wasn't stopped.

Removed nonsense code, that I should have check more in details before merging m(

Allow easier monkey patching of WAMP connector Session class

Expose new PLCObject API members to WAMP interface.

Use another way to ensure compatibility with Py3 about text type.

Make easier to read console error message in case of connection problem.

PYRO(S): Added timeout on client side to allow unfreezing IDE after some time when communication with target dropped

Enure that autostart blocks other @RunInMain PLCObject methods, and _unblocks_ them once autostart is done...