New MIB stuff, typo fixes, and basic gentoo init support

I added some extra stats that my team was interested in tracking, and I fixed some typos that I found while I was updating the MIB (for example, it claimed to represent MySQL statistics, so I guess that you copied it from your "mysql-snmp" project).

Anyway, things seem great, and I've built a gentoo ebuild for it that utilizes the two files in the "gentoo" directory, and everything's doing just fine.

Unrelated, but something I noticed: your indentation seems arbitrary and random.  I recommend using tabs in a deterministic matter; it removes any ambiguity and is easily enforceable by most editors.  I didn't mess with it, and I used whatever arbitrary amount of spaces were present for all of my changes.