Some misc settings in ome-miscs.org.

All settings which didn't fit anywhere will be put in ome-miscs.org. As
ome-miscs.org grows, there may be some code be refactored out to form a new
topic file.

Current miscs settings include:
- seed random number when emacs starts
- toggle on auto-compression-mode
- toggle on auto-image-file-mode
- globally enable rainbow-delimiters mode