update to ec2-plugin and new java heap monitor

Hi Scout! 

ec2 plugin
I'm the author of your ec2 plugin.  Just noticed it was using iostat data averaged since the system booted.   I've updated to pull the latest data sample.

new Java heap plugin
I also would like to submit a new plugin for consideration.  It pulls the java heap size used out of jmap.  
I don't use the JMX plugin (which can provide heap used) currently on available b/c we disable the JMX console to avoid security issues.

~Ken