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

This reverts commit ce6ad78d80b1a78c82d1ba9450fb810480d3c04c.
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.
Selectivities shouldn't be identical to 0 because of integer division.
Merge pull request #3471 from pontusmelke/bug-in-test

Selectivities shouldn't be identical to 0 because of integer division.
Merge pull request #3436 from jakewins/2.2-restprops

Replace 204 response with empty map for get empty properties, fixes #83.
Tiny rewriter that changes WHERE x IN [1] into WHERE x = 1
Merge pull request #3474 from systay/simplify-in

Tiny rewriter that changes WHERE x IN [1] into WHERE x = 1
Added ability to trigger index sampling from shell.

Usage:
```schema sample -a```
will sample all indexes.
```schema sample -l Person -p name```
will sample the index on index the for label 'Person' on property 'name' (if existing).