Fixed #47

If a channel Name contains only numbers, it will now add a prefix "num_"
to the name. Using the same method as for catching the special caracters
to fix it.
Also added the ':' to the list of bad caracters
Cleaned the code in the WireBox (duplicated method isActive() )
Welcome to 1.8.6b!

I'll have to fix many bugs and do some improvements before to release.