Client version

This sets new versions in the meridian client.
I've chosen "50" as new major revision to hopefully not overlap with the original client.

Both values are at least limited to a max value of 255.
For minor_revision it states 0-99.

These values (mostly the minor) must be raised whenever a new meridian.exe is distributed with a client-update/we changed something in the client.

The server's blakserv.cfg must reflect this.