Fix misspellings.
Drop the heap and RAM used from _cat/nodes and add the RAM percentage.

In this view you never care about the actual heap used bytes; you only
want to know that your max is set to what you meant and what
percentage you're currently using.

Closes #4151.
Add full_id param to support displaying entire node ID.
Add _cat/help (halp!)
Add load average to _cat/nodes.
First pass at cat docs.
Allow native scripts to set the value of a script field to primitive arrays

Script fields could not be set to int[] and float[] by native
scripts because StreamInput and StreamOutput could not handle
them.

closes #4175
Re-enable snapshot/restore tests that were failing on windows