Built-in assets are now installed as paks instead of "loose" files.
There was a bug which caused some files to be not installed properly.
It's now addressed by this commit. (Fixes#430)
It should be now possible to launch OpenSpades without `make install`.
Just make sure to cd to the build directory (where you ran `cmake`) before
launching OpenSpades by `bin/openspades`.
2872e4e66e