Fix errors in lookup plugins.

Lookup plugins 'sequence' and 'template' now import 'ansible.utils'
appropriately in order to use the 'listify_lookup_plugin_terms'
function.

Also, 'dnstxt' and 'env' now check to see if 'terms' is a string;
without this calls like '{{ lookup('env', 'HOME') }}' fail.
Merge pull request #2700 from chamill/devel

Fix errors in lookup plugins.
Fix 'sequence' plugin error.

If 'terms' is a string, replace it with a single item list.
Merge pull request #2701 from chamill/devel

Fix 'sequence' plugin error.
Fix if-statement that always evaluates True
Merge pull request #2705 from b6d/utils-fix

Fix if-statement that always evaluates True
(A) include errors in inventory scripts should they occur.

(B) allow registration with ignore_errors: True
correct reference to module
Merge pull request #2712 from lwade/devel

correct reference to module
Revert "make atomic_replace use shutil.copy2 instead of os.rename() so it will work across filesystems".

AR function was leaving some tmp files behind, want to revert, will have better implementation soon, this is the old way now.

This reverts commit f74a1fa4f0b1a928a85c1316dfceb42637624a2f.
clean up first_found to fix a few issues:

 - add a skip option so it won't raise an exception if you don't match anything
 - make it work as a drop-in replacement for first_available_file
 - document in the module comments all of the above cases
Merge pull request #2716 from skvidal/first_found_skip_fix

clean up first_found to fix a few issues: