Improve the visualization of the bigswitch rules

[frisso]

In the summary view, show only the rule name and, if available input/output port.
A new option should be available to show the list of flow rules (with the most significant fields) as a table. Aside each rule, a dedicated button should be used to show the complete rule, hence also the fields that are not shown in the table.
This mimics what OpenDayLight Hydrogen does:
https://wiki.opendaylight.org/view/File:FlowStatitistics.jpg

Important: the list of fields shown in the table should be easily customizable, e.g., through a simple (text) list.