implemented node network stats
documentation for node load metrics
implemented os expression on sys.nodes
added changelog entry for os expression on sys.nodes
implemented process expressions on sys.nodes
implemented max_open_file_descriptors expression
changed output of colum names in information schema to subscript notation
changed sys.nodes.fs to contain total and separate disk stats and node data path locations
increase version for feature branch
Merge pull request #934 from crate/load-metrics

Load metrics
avoid creating new Ordering instances in ColumnIdent compareTo