Improved tag detection

This should improve client tag detection. Some clients have IDs, part between "<" and " V:", with numbers, dash and space in it. Others have "v:" instead of "V:", so these parts now support lowercase letters aswell, like "m:A" or "s:3". Also there have been reports of user modes like "M:AP", something like active and passive together, don't know what is the point of that, however, unknown modes are now supported too and are detected as passive.