Fix bug 1154881 - Documenting PLUMgrid plugin

In this commit we add the description of the PLUMgrid plugin for Quantum.

Change-Id: I3b18e939a727c9faf2002beacb4d40fb4e95d93a
Update Storwize/SVC driver documentation.

This update reflects changes made to the Storwize/SVC driver for the
Grizzly release.

Change-Id: Ie68e895898afc7cdd6830ba709b35b1d8bff9b69
Add table describing q-plugin compat with nova drivers.

bug #1104828

Also removed some broken links to readme files, and added some
missing plugins to the overview page.

Change-Id: I5c2713148aa0d0c09176e8b2d84d810a8d68daf8
Merge "Fix bug 1154881 - Documenting PLUMgrid plugin"
3PAR Block Storage Driver space character issues

The Block Storage Admin Guide PDF in the HP 3PAR Fibre Channel
and iSCSI driver section could add a few spaces to improve readability
in the Supported Operations section. This fixes the following few lines:

provisioning - Defaults to thin provisioning, the valid values are thinand full.
<need to add a space character after thin and before and>

persona - Defaults to the 1 – Genericpersona.
<need to add a space between Generic and persona>

Change-Id: I7278ea2c4ba43003ccce4fcf43bc233b3b2760c3
Fixes: bug 1167468
Merge "Add table describing q-plugin compat with nova drivers."
Merge "Update Storwize/SVC driver documentation."
Merge "3PAR Block Storage Driver space character issues"