vlc.py - Allow VLC_MAX_PORT to be set to the same value as VLC_MIN_PORT

Avoids empty range ValueError
Add VLC version checking code to vlc.py

Complains if VLC version is less than 2.0.6
Add VLC version mismatch message text to messages.py
Merge pull request #21 from Et0h/master

VLC version checking and min/max port fix