Connection idle timer CSHARP-198
Raise event when idle request fails CSHARP-198
Host fires down events, ControlConnection and Metadata subscribes to those events.
Add 2 pool related tests: amount of connections and dns resolve
Hearbeat: pool subscribe to idle request exception CSHARP-198

- Dispose connections when node is down
- Check if its being disposed
- Add test HeartbeatShouldDetectNodeDown
Add 2 connection test on heartbeat CSHARP-198
Removed inconclusive test
Test: BoundStatements with wrong numeric values
Test: BoundStatements with wrong collection values
BoundStatement parameter types validation
Merge branch '2.1'

Conflicts:
	src/Cassandra.IntegrationTests/Core/PoolTests.cs
	src/Cassandra/Connection.cs
	src/Cassandra/ControlConnection.cs
	src/Cassandra/Host.cs
	src/Cassandra/HostConnectionPool.cs
	src/Cassandra/Hosts.cs
	src/Cassandra/Metadata.cs