Use an "IP generation mask"

Use a special mask to generate IP addresses. This
is named ipgeneratemask. If none is specified,
it will fall back to using the netmask field.
Serval-specific changes

Default servald status to false and add
support for a special servaldsid field.
Use ipgeneratemask in defaultPlug profile
Merge git://github.com/hawkinswnaf/commotiond into hawkinswnaf-master

Resolved conflict with defaultPlug config file.