Fix #159: Don't use /tmp as the path for temp files in the tests"
In issues.lisp, instead of using "/tmp" for the temporary directory, use a temp directory relative to the the current directory. This fixes an issue with CI where if I run the tests manually locally the temp files are created in "/tmp" with my uid. When CI runs it wants to create the same files, but uses the CI uid and hence can't create the files.