[BZ 958922] RFE: support for passing plugin config when creating child
resources

Now we support all 4 possible 'ways' to create a resource on RHQ

1. regular resource (was already implemented) - when REST client create
resources that agent would have discovered. Such resources is not possible
to create via UI or CLI

2. content-based resources (was already implemented)

3. resource children: similar to content-based resources, UI analogy is
"Create Child". Create child history exists. - possible resource duplicities
are handled on agent side.

4. manual resources: Resources that could be only manually Imported from UI,
create child history does not exist for those, and their resource key highly
depends on given pluginConfiguration (although resourceName can be passed).
Duplicates are handled on server side, since underlying API does not report
an error when manually imported resource already exists.

For 3. and 4. there's client can optinaly pass only required plugin/resource
configurations. In rest api code, we retrieve all the defaults from resource
type and then apply passed values on top.
[BZ 1069679] Expose responseTime metric via rest

callTimes are exposed via endpoint GET /metric/data/{scheduleId}/callTime
supported are both aggregated (default) and 'raw' callTime data. CallTime
values can be pushed via PUT /metric/data/{scheduleId}/callTime. Note that
data retrieved via GET has different format as what is pushed. User pushes
really RAW callTimes (time,callDestination,duration) but he *always*
recieves aggregates.
added new lines between methods
Merge pull request #13 from lzoubek/bugs/958922

[BZ 958922] RFE: support for passing plugin config when creating child
Merge pull request #5 from lzoubek/bugs/1069679

[BZ 1069679] Expose responseTime metric via rest
[BZ 1075575] Update Cassandra to a version specially crafted to not print the superfluous warning about OpenJDK.
BZ 823965 Maintain existing agent-configuration.xml and log4j.xml files after agent auto-update.
The new configuration will be kept in agent-configuration.xml.new and log4j.xml.new
so that we at least provide the user with the updated defaults in case they want to manually merge them.