Fix fetch of NPI plugin

Was not grabbing the key
Update cache when installing Java
Typo of update_cache
Template newrelic.json for plugins
Add additional newrelic.json settings
Add mysql plugin to example playbook (and tests)
Forgot npi_plugins key
Making Java a prerequisite and requiring installation of nodejs

Rather than installing as part of this role. Because of the variances
with preferences of how to install Java and/or NodeJS it felt better to
leave them as prereqs.
Use sudo in Travis when installing java and nodejs
Use sudo when apt-getting on Travis
Debugging Travis node version
More Travis debugging
Even more Travis debugging
Looks like node should already be installed on Travis
More Travis debugging
Trying to use `nvm` so node is available
Symlinking node so that ansible can use it

PATH is different when ansible ssh's
Using sudo to link node
Specify new_relic_license_key in example playbook
Remove Travis debugging messages