Added missing headers to fix 'make dist'.

Looks like make dist is broken on master:

make dist works, but when running make on the extracted distribution:

Making all in scheduler
  CXX      compileserver.o
compileserver.cpp:24:27: error: compileserver.h: No such file or directory
compileserver.cpp:32:17: error: job.h: No such file or directory
...