LINUX
* Added a "notifier_chains" plugin, to output the callbacks of Linux notifier chains.
* Added a "mcat" plugin to dump the contents in memory of files in mounted filesystems.
* Added a "psxview" plugin to compare different process listing plugins.
* Relaxed the kernel version regexp in guess_profile.
* Added a quick verification of guessed kernel profiles.

BUG=
R=scudette@gmail.com

Review URL: https://codereview.appspot.com/104200043