Prior to this change it was intermittently failing with:
```
net.corda.client.rpc.RPCException: RPC server is not available.
at net.corda.client.rpc.internal.RPCClientProxyHandler.invoke(RPCClientProxyHandler.kt:222)
at com.sun.proxy.$Proxy79.ping(Unknown Source)
at net.corda.client.rpc.RPCStabilityTests$client reconnects to rebooted server$1$pingFuture$1.invoke(RPCStabilityTests.kt:251)
at net.corda.client.rpc.RPCStabilityTests$client reconnects to rebooted server$1$pingFuture$1.invoke(RPCStabilityTests.kt:36)
at net.corda.core.internal.concurrent.ValueOrException$DefaultImpls.capture(CordaFutureImpl.kt:107)
at net.corda.core.internal.concurrent.OpenFuture$DefaultImpls.capture(CordaFutureImpl.kt:65535)
at net.corda.core.internal.concurrent.CordaFutureImpl.capture(CordaFutureImpl.kt:119)
at net.corda.core.internal.concurrent.CordaFutureImplKt$fork$$inlined$also$lambda$1.run(CordaFutureImpl.kt:22)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:748)
```
* Improve error reporting in case of failure of flaky tests
Also eliminate warnings and other minor changes.
* Address code review comments raised by @exFalso
Also improve output for stack traces.
* Fix `IRSSimulationTest` test
Since prod class `IRSSimulation` loading `trade.json` as resource, `trade.json` should be located in prod resources folder of a dependant project to be successfully loaded.
Also improve error reporting.
* Change of Json trades samples locations
* CORDA-1208: Notary service should persist the notarisation request signature along with the committed input states.
This required modifying the uniqueness provider interface to accept the signature in addition to input states.
Until now the committed state log used to be stored as a map of (state reference -> (tranasction id, consuming party)).
Adding the serialized signature would mean inflating each state entry by around 700 bytes, which would be grossly inefficient.
Instead, two tables are now used: one for storing (state referece -> transaction id) map, and another for storing the notarisation
request details (transaction id, consuming party, date, signature).
* Update api - all of these changes are only related to custom notaries
Old code failed with:
```
11:34:01.536 [main] ERROR net.corda.node.internal.Node - Exception during node startup
java.nio.file.InvalidPathException: Illegal char <:> at index 2: /C:/Program%20Files/JetBrains/IntelliJ%20IDEA%20Community%20Edition%202017.3.1/lib/idea_rt.jar
at sun.nio.fs.WindowsPathParser.normalize(WindowsPathParser.java:182) ~[?:1.8.0_144]
at sun.nio.fs.WindowsPathParser.parse(WindowsPathParser.java:153) ~[?:1.8.0_144]
at sun.nio.fs.WindowsPathParser.parse(WindowsPathParser.java:77) ~[?:1.8.0_144]
at sun.nio.fs.WindowsPath.parse(WindowsPath.java:94) ~[?:1.8.0_144]
at sun.nio.fs.WindowsFileSystem.getPath(WindowsFileSystem.java:255) ~[?:1.8.0_144]
at java.nio.file.Paths.get(Paths.java:84) ~[?:1.8.0_144]
at net.corda.node.utilities.JVMAgentRegistry.resolveAgentJar(JVMAgentRegistry.kt:46) ~[classes/:?]
at net.corda.node.internal.AbstractNode.initialiseJVMAgents(AbstractNode.kt:785) ~[classes/:?]
at net.corda.node.internal.AbstractNode.start(AbstractNode.kt:199) ~[classes/:?]
at net.corda.node.internal.Node.start(Node.kt:335) ~[classes/:?]
at net.corda.node.internal.NodeStartup.startNode(NodeStartup.kt:146) ~[classes/:?]
at net.corda.node.internal.NodeStartup.run(NodeStartup.kt:120) [classes/:?]
at net.corda.node.Corda.main(Corda.kt:16) [classes/:?]
```
* rework message handling while connection is down: do not send anything, throw on all obs and futures when failure detected
* RPC calls will throw if used during failover; adapted tests
