Split native collector into it's component parts and make them enablable.

Last login is disabled by default as it's broken on ubuntu 12.04
Interrupts is disabled by default as it's very granular and we'll have total interrupts from /proc/stat

Allow ignoring devices from diskstats, ignore ram and loop devices by default.

Use glog for logging.
Fix typo
Add option to print out available collectors.

Fix typo.
Ignore disk partitions by default, it's the disks themselves you usually want.
Merge pull request #12 from brian-brazil/seperate-modules

Split native collector into it's component parts and make them enablable...