adding graphite plugin to bosh-monitor
bosh-monitor-graphite: refactored tsdb connection/graphite connection, extracted common parts into separate tcp_connection class
bosh-monitor-graphite: added graphite plugin options in template
Set bosh monitor config in tests

Running individual tests fails since config is not set

Signed-off-by: Maria Shaldibina <mshaldibina@pivotal.io>
Refactor graphite monitoring

Signed-off-by: Maria Shaldibina <mshaldibina@pivotal.io>
Merge PR #714 into develop

Signed-off-by: Maria Shaldibina <mshaldibina@pivotal.io>