Fix /proc/stat check in the procstat plugin

Catches the exception thrown when /proc/stat is not present.
Merge pull request #1 from blom/master

Fix /proc/stat check in the procstat plugin
Fixes #15: Trim leading whitespace in /proc/net/dev
Fix #14: Don't do parseInt on Number.
New plugin: Diskstats
Add initial memory plugin
Merge git://github.com/blom/pupil

Conflicts:
	etc/config.json
Plugin memory: Moved cache above used.
Refactor: Make plugins into classes.
Refacter: Make plugins into classes #2
Fix error after refactoring
Allow multiple instances of plugins.
Plugin procstat: Graph of blocked processes.
Use rickshaw series to expire and add data.

Fixes #18
Add expand/collapse plugin-list

Fixes #8
Fix footer.
New plugin: vmstat
Prevent connection subscribing to same graph multiple times.

Fixes #20.
Ignore silly OSX files.
Merge remote-tracking branch 'upstream/master'