Checks for "init_settings" and "runtimesettings"

When ever settings are updated checks are performed and if either
runtimesettings or init_settings are missing (or perceived as missing)
from a reporter or interfacer settings it will not update/delete or
rebuild, it will ignore the changes log a warning and move to the next,
simply correcting the error in the conf file will  result in business as
usual
Configuration file section checks

At start up and at every change to the settings file it is checked for
the 3 compulsory sections. At start up up emonhub cannot start but will
point user to the section causing an issue/missing. During normal
running if a user save the file with one of the sections missing the
changes are ignored until rectified.
Merge pull request #101 from otherWIP/testing

Configuration file checks