Add install target to makefile
Replace hardcoded path with system one
Revert "Temporarily change logging level because logging.DEBUG does not work."

This reverts commit b5dcbf4724effe2c9e66075d1a9c306caa8051b0.
Don't remove producer name from cache after commit

Rationale is that after a commit the file will not be opened for writing
again. Thus, if CIEL does, however, for any reason retrieve the producer
filename, we won't open a never-to-be-used writer fifo.
Add some more logging output
Set appropriate logging levels
HACK to avoid a stat() call and also to avoid string-over-http transfers