Add online resize support (#694622)

Many file systems are capable of growing while mounted, and a few can
even shrink.  This support must be explicitly enabled at configure time
with the --enable-online-resize flag and depends on a patched libparted.
Also requires kernel >= 3.6 for partition resizing, even if the
partition is in use (BLKPG_RESIZE_PARTITION).

Thanks to Mike Fleetwood for double check mark idea instead of a second
column to show the online grow/shrink.

Bug #694622 - Add support for online resize
Update help manual for online resize support (#694622)

Indicate that online resize is available for some mounted or otherwise
active partitions.

Bug #694622 - Add support for online resize