Converted Golang format source code by goimports.
Starting develop linux plugin.
Add vmstat parse logic.
Create get ss status methods.
add indices.memory_size graph (fielddata & filter_cache)
Add disk read/write time metrics.
Add /proc/stat metrics.
It can get metric selected.
Add test for collect methods.
Add users metric.
Update comment.
Add readme file.
Merge pull request #27 from naokibtn/feature-elasticsearch

Elasticsearch: add indices.memory_size graph (fielddata & filter_cache)
Output metrics information.
Fix label.
Stacked graph supported toward scoreboard and workers.
Fix readme.
Merge github.com:mackerelio/mackerel-agent-plugins
Merge github.com:mackerelio/mackerel-agent-plugins into linux-metrics
Merge branch 'master' into linux-metrics