Expose Node degree in REST API.
Replace 204 response with empty map for get empty properties, fixes #83.

- This makes client-side code slightly simpler, since it removes an edge case
  entirely - just return an empty map for empty properties.
- The 204 response was undocumented, so this does not break documented
  behavior.
- Remove duplicate integration tests, replace with simple full-stack test.
Fixes #3017

Changes behaviour for the simple CASE so that null as comparator results in the else expression being used
Merge pull request #3445 from petraselmer/null-case

Fixes #3017
Revert "Merge pull request #3445 from petraselmer/null-case"

This reverts commit ca1dde385209043ac25ab65fbe4ee2072385c83f, reversing
changes made to 3d722bc57520c498d62bf24e6074f023eb4824af.
Tweaks for import tools docs.
Improve test speed by using an ImpermanentGraphDatabase
Cancel index sampling when index is dropped
Merge pull request #3406 from jakewins/2.1-rest-degree

Expose Node degree in REST API.
Merge branch '2.1-maint'

Conflicts:
	community/server/CHANGES.txt
Added JMX controls for triggering index sampling.
Revert "Revert "Merge pull request #3445 from petraselmer/null-case""

This reverts commit ce6ad78d80b1a78c82d1ba9450fb810480d3c04c.
Merge pull request #3468 from digitalstain/master

Merge branch 2.1-maint into master
Merge pull request #3456 from petraselmer/jmx-trigger-sampling

Added JMX controls for triggering index sampling.
Merge branch '2.0-maint' into 2.1-maint

Conflicts:
	community/cypher/cypher-compiler-2.1/src/main/scala/org/neo4j/cypher/internal/compiler/v2_1/commands/expressions/SimpleCase.scala
	community/cypher/cypher-compiler-2.1/src/test/scala/org/neo4j/cypher/internal/compiler/v2_1/commands/expressions/GenericCaseTest.scala
Lingering edits that should have made it into the last commit.
Merge branch '2.1-maint' into master

Conflicts:
	community/cypher/cypher-compiler-2.2/src/main/scala/org/neo4j/cypher/internal/compiler/v2_2/commands/expressions/SimpleCase.scala
	community/cypher/cypher-compiler-2.2/src/test/scala/org/neo4j/cypher/internal/compiler/v2_2/commands/expressions/GenericCaseTest.scala
Remove unnused import
Fixing build errors
Merge pull request #3469 from nawroth/import

Tweaks for import tools docs.