Added test for slave-only instance being elected coordinator
Fixes so that slave-only instances not only try not to win elections, but actively don't switch to master in the case they are coordinators (e.g. because the instance created the cluster)

Conflicts:
	enterprise/ha/src/main/java/org/neo4j/kernel/ha/HighlyAvailableGraphDatabase.java
	enterprise/ha/src/test/java/org/neo4j/ha/TestSlaveOnlyCluster.java
Changes ClusterSettings.server_id to be an InstanceId instead of an integer
Fixed merge issues
Merge pull request #2353 from digitalstain/1.9-maint

Changes ClusterSettings.server_id to be an InstanceId instead of an integer
Merge branch '1.9-maint' into 2.0-maint

Conflicts:
	enterprise/cluster/src/main/java/org/neo4j/cluster/ClusterSettings.java
	enterprise/ha/src/main/java/org/neo4j/kernel/ha/SlaveStoreWriter.java
	enterprise/ha/src/main/java/org/neo4j/kernel/ha/cluster/zoo/Machine.java
	enterprise/ha/src/main/java/org/neo4j/kernel/ha/cluster/zoo/ZooClient.java
	enterprise/ha/src/main/java/org/neo4j/kernel/ha/cluster/zoo/ZooKeeperHighAvailabilityEvents.java
	enterprise/ha/src/main/java/org/neo4j/kernel/ha/cluster/zoo/ZooKeeperMachine.java
	enterprise/ha/src/main/java/org/neo4j/kernel/ha/com/master/MasterImpl.java
	enterprise/ha/src/main/java/org/neo4j/kernel/ha/transaction/TxIdGeneratorModeSwitcher.java
	enterprise/ha/src/test/java/org/neo4j/ha/TestPullUpdates.java
	enterprise/ha/src/test/java/org/neo4j/ha/TestSlaveOnlyCluster.java
	enterprise/ha/src/test/java/org/neo4j/ha/TransactionConstraintsIT.java
	enterprise/ha/src/test/java/org/neo4j/kernel/ha/TxPushStrategyConfigIT.java
	enterprise/ha/src/test/java/org/neo4j/test/ha/ClusterManager.java
	enterprise/ha/src/test/java/slavetest/TestStoreCopy.java
Merge pull request #2365 from digitalstain/2.0-maint

Merge branch 1.9-maint into 2.0-maint
Merge pull request #2341 from rickardoberg/slaveonlyfix2

Slave-only instances no longer becomes master