* Add junos_system declartive module and other related change
* junos_system declartive module
* integration test for junos_system
* integration test for net_system (junos platform)
* pep8 fixes for junos modules
* move to lxml from elementree for xml parsing as it support
complete set of xpath api's
* other minor changes
* Fix CI and doc changes
* Fix unit test failures
* Fix typo in import
* Fix import issue for py2.6
* Add missed Element in import
