Status lines updates, rtslib 3.0-pre4 compatibility

Updated to use nexus_wwn TPG attribute

* In rtslib, the TPG.nexus attribute has been renamed nexus_wwn
* Clarified the status line a little bot for nexus_wwn

Bugfixes, packaging

This release has been tested on centOS/RHEL 6.5 and 7 as well as Debian Wheezy and Jessie. The corresponding packages are attached to the release.

Native save/restore, new config mode subshell, kernels up to 3.14 and more

Native save/restore, new config mode subshell, kernels up to 3.14 and more