Bug 1280: Added option to automaticly create parents

Introduced additional variation of put and merge
which allows user to specify if parents nodes
are to be created. Default behaviour is to not
create parent nodes, but users still have
explicit API for creating them if necessary.

Updated documentation accordingly and added note
that auto-create of parents may potentially
create garbage in data store.

Change-Id: Id4a88b015e05b4717e9c393ddf821c7f93e7e541
Signed-off-by: Tony Tkacik <ttkacik@cisco.com>
Merge "Bug 1280: Added option to automaticly create parents"