XML bug fix

Missing closing tag making the XML invalid

ntp implementation for Cisco switches

we can now use a method called set_vlan_ntp_state in the API to set the
ntp state on Cisco switches

set_vlan_ntp_state to 'false' will trigger a 'ntp disable' on the
specified vlan interface.
set_vlan_ntp_state to 'true' will trigger a 'no ntp disable' on the
specified vlan interface.

Merge pull request #217 from lindycoder/icmp_redirect_mx

Implement set_icmp_redirects for juniper_mx

Add the vrrp information to the vlan objects