bump version to 1.5.1 RC3 - I didn't touch gameversion as we're
drwxr-xr-x - Docs
drwxr-xr-x - TeamNexuiz
drwxr-xr-x - attic
drwxr-xr-x - data
-rwxr-xr-x 18009 gpl.txt
drwxr-xr-x - navnodeedit
-rwxr-xr-x 239 nexuiz-linux.sh