Added network ifaces collision checking to HA floating IPs
Checking interface and DHCP fixed IP collision

 * Improved the previous implementation of network checking
Fixed previous commit
Added a getter method to get the existing floatingIPs
Added DHCP ranges collision checking
Added a method to check if a given IP is already a floating IP
Check HA floating IP collision when creating DHCP range
Check HA floating IP collision when adding a new DHCP fixed address
Use appropiate hash element to get the IP address
Removed relic-venerable unused code
Completed sub comment with new HA constraint
Check HA floating IP collision when adding a new virtual interface
Check HA floating IP collision when adding a new static interface

 * Also a small refactor from previous commit
Include PSGI app to expose cluster to other servers

Using a custom router as web framework here is not yet possible.
RESTClient is now part of core

* As it is used by ha and remoteservices module.
* run-pending-ops has been moved to core as well
* RESTClient has been unit tested a little
Added empty to NodeList
Document hostName and fqdn for developers
Added localNode attribute to nodelist elements
Added several capabilities to ha.psgi daemon

* Decode JSON from body
* Added return simple scalar
Adding support to named parameters in Router

We are now copying without blush to Django URL dispatcher