Allow switching between file systems while running

Bind the 'f' key in ltop to bring up a menu allowing selection from a
list of filesystems available for monitoring.  Also update
_find_first_fs() to use the new helper function _find_all_fs() and
ignore filesystems with no OSTs.

Closes #3
Updated to use *_2_0_MDT_STATS for BACKFS_ZFS

The current Lustre-Orion code uses the same "md_stats" file for it's MDT
statistics as Lustre 2.0; no longer using the Lustre 1.8 "stats" file.
This patch updates _build_osd_stats_path to account for this change.

Signed-off-by: Prakash Surya <surya1@llnl.gov>
Closes #13
Prep for 3.1.4 release
Correctly redisplay OST window

Two bugs caused the OST window to not redraw correctly
after selecting a new filesystem to monitor:

1) The repoll variable wasn't reset after polling so
   the ost_data list was always being emptied

2) The ost window needs to be recreated with more lines
   if the new filesystem has more OSTs.
Prep for 3.1.5 release
Update Packager and URL in spec file
Add .gitignore files
Add code comment for _get_iops()
Ignore missing brw_stats in the osd directories.

As of 2.3.64 (probably earlier too) we have lost obdfilter's brw_stats,
and the new OSD proc directories lack that file, or any other clear
way to get the information that we need.
Bump version to 3.1.6 and run autogen.sh