The messages now show where the request failed and what was
requested. This should help resolve both develper and end-user problems.
Also fixed the missing logging of the output string in the `parse`
callback of the main function and cleaned up the POSTed server body.
The monitors should only be reused if they have the same name and they use
the same module. This way the only difference is in configuration.
Fixed MaxCtrl detection of bad options and altered monitor creation test
to expect correct results. Also improved some of the error messages.
The `cluster diff` command prints out the difference between the source
and target MaxScale. This allows users to detect changes that have
happened on one MaxScale but not on the other.
Making the core a module proved to bring more problems than it solved. For
the sake of simplicity in installation and code coverage reporting, the
core is now completely contained in the `lib/` directory.
Also added preliminary coverage reporting with nyc.
