Handle clusteringEnabled == NO case
<KPTreeControllerRework>: add treeControllerShouldClusterAnnotations:
Create KPConfiguration class to hold configuration settings
Remove old KPTreeController
Test-related changes:
* upgrade to xctool 0.1.15
* tests now run using iphonesimulator7.1
Merge branch 'master' of https://github.com/itsbonczek/kingpin
Always declare memory-management semantics even on readonly properties.
Make _animateCluster: a private method
Add -Wall and -Wpedantic flags and fix corresponding compiler warnings
Various changes to address Refactoring 1, #32

- KPGridClusteringAlgorithmConfiguration is introduced to be a @configuration property of KPGridClusteringAlgorithm. It now holds gridSize property.
- Grid-based bucketing was moved away from KPTreeController, it is now a part of KPGridClusteringAlgorithm.
GridClusteringAlgorithmDelegate, new method (#32)

- gridClusteringAlgorithmObtainGridCellSize:forMapRect: connects grid
  clustering algorithm and KPTreeController.
KPGeometry: add first test (#32)
Rename: buildTree() --> kp_tree_build()
Better name: gridClusteringAlgorithm:obtainGridCellSizeForMapRect:
Use CLLocationCoordinate2DDistanceToCoordinate instead of -[CLLocation distanceFromLocation:]
A test for KPClusterGridCellPositionCompareWithPosition and some cleanups
KPClusterGridCellPositionCompareWithPosition() - more thorough test
Fix grid size calculation
KPClusterGridCellCreate()
_mergeOverlappingClusters: add simple test