power_system to take user/pass

And supply them to api calls rather than None
Merge pull request #770 from nitinz/master

sub power_system to take user/pass
Fix the way openSUSE finds the tree

It has no kickstart so use the same logic as debian/ubuntu. Extract the
tree location from ks_meta[tree].

(REVIEW with diff -b (ignore space changes))
Two more places to put "opensuse" beside "suse".

Found with grep. I think they belong here.
Merge pull request #771 from jansenm/opensuse-fixes

Opensuse fixes
Added signature for SLES 12.
Update for SLES for VMware.
Merge pull request #772 from sidrew/master

Added signature for SLES 12.
Nexenta support
reworking the patch for the branch master.
putting install_profiles of nexenta into nfs, not tftp.
Fix indentation in koan/app.py

Making RPMs on Fedora 20 fails with:

    Bytecompiling .py files below .../cobbler/rpm-build/BUILDROOT/cobbler-2.5.0-1.fc20.x86_64/usr/lib/python2.7 using /usr/bin/python2.7
    Compiling .../cobbler/rpm-build/BUILDROOT/cobbler-2.5.0-1.fc20.x86_64/usr/lib/python2.7/site-packages/koan/app.py ...
    Sorry: IndentationError: unindent does not match any outer indentation level (app.py, line 693)
    error: Bad exit status from /var/tmp/rpm-tmp.OgToE3 (%install)
Merge pull request #775 from ciupicri/bugfix-indentation

Fix indentation in koan/app.py
New template files needed for ESXi 6.0
Fix manpage: server-override -> server
Added ESXi 6.0 signature.
Minor changes to support ESXi 6.x distros.
Merge pull request #777 from jmaas/master

Fix manpage: server-override -> server
Merge pull request #774 from piousbox/master-nexenta

Nexenta support
Merge pull request #776 from sidrew/master

Template changes/additions and pxegen.py updates to support ESXi 6.x distros.