docs: Rework of 'README.md'

- Remove duplicated text from README, like build instructions. These
  are too likely to get out of date.
- Remove references to 01.org DPDK vSwitch page, which has been removed
  in favour of this documentation.
- Use relative links to documents in place of absolute ones, to ensure
  the user gets the correct version of a document (i.e. development
  version rather than master)

Change-Id: Ib48424d86762340dde09b0e9658078cbe69a8480
Signed-off-by: Stephen Finucane <stephen.finucane@intel.com>
Reviewed-by: Kevin Traynor <kevin.traynor@intel.com>
Reviewed-by: Mark B. Kavanagh <mark.b.kavanagh@intel.com>
docs: Update reference to ovs_client application

The wrong path was given for this application. Fix it.

Change-Id: I6c2e1cf7126fb7b2caa8141efa8adc14000f8aa7
Signed-off-by: Stephen Finucane <stephen.finucane@intel.com>
Reviewed-by: Kevin Traynor <kevin.traynor@intel.com>
Reviewed-by: Ciara Loftus <ciara.loftus@intel.com>
docs: update to Known Issues

Change-Id: I8cfbca4081a626706e2070cb7f5477d1217635b0
Signed-off-by: Kevin Traynor <kevin.traynor@intel.com>
Reviewed-by: Stephen Finucane <stephen.finucane@intel.com>
Reviewed-by: Mark B. Kavanagh <mark.b.kavanagh@intel.com>
dpif/tests: Remove unused variable & fix UTs

* Remove unused variable from dpif get_stats function
* Repair broken port-get-stats unit tests

Change-Id: Ic22f34c3b57f0e25224af8f7cccd61d87eb9e49c
Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Reviewed-by: Kevin Traynor <kevin.traynor@intel.com>
Reviewed-by: Stephen Finucane <stephen.finucane@intel.com>