This is game code of Rexuiz.
You need to have rmqcc installed. Use make command to build the mod.
make QCC=/path/to/rmqcc
Copy 1vs1.dat, 1vs1.cfg and cl_1vs1-*.pk3 to your ~/.nexuiz/data or ~/.rexuiz/data directory.
Add this line at beginning of server.cfg:
exec 1vs1.cfg
Check out 1vs1.cfg for available cvars. Most of them are not documented very well, it's a work in progress.