Fix check for existing IP Address in DHCP mapping

Even the Error message says: "This Hostname, IP or MAC address already exists." the IP Address was not checked if it already was given to a client as static mapped
Force apinger to write the status file before getting gateway status
Merge pull request #770 from individual-it/master

Fix check for existing IP Address in DHCP mapping
Make sure an alias is not used by a static route before delete, ticket #2941
Declare globals as global before defining them in openvpn.inc
Remove prior CSC entry when cleaning up. Fixes #3143
Fix double-click to edit on OpenVPN CSC entries
Relax advanced options firewall rules tests

Various advanced options are now possible for any protocol since https://github.com/pfsense/pfsense/commit/653bde345e8f960de5bc745fe74e64d8ef3fd2d3
So allow these through the front-end GUI validation also.
Merge pull request #773 from phil-davis/master

Relax advanced options firewall rules tests
Display pfSense interface name on status interfaces

Sometimes it is a bit difficult to work out which interface descriptive name is which pfSense internal interface name (wan, lan, opt1, opt2...). It is useful to know for:
a) hardware that has wan, lan, opt1... pre-printed on the case (some Alix cases for example), making it easier for less-trained remote office staff to work out which cable corresponds to which interface in pfSense.
b) looking in config.xml or other techo places where the internal pfSense name is stored/referenced - knowing that straight from a status GUI display saves having to first find the descriptive name in the config, then the pfSense internal name.
What do you think? Is this a worthwhile place to display this data?
Merge pull request #775 from phil-davis/master

Display pfSense interface name on status interfaces