Custom JSON loader

Added a method in the Loader that enable the load of custom json files,
to be used like a the general settings of the game.

loading: game.load.json (key, url);
retrieving data from json file: game.cache.getText(key);
Added a warning when the expected image dimensions of the tile set do not match the actual dimensions.
Return a value from Phaser.Physics.Arcade.intersects.
Fix typo of Phaser.Key#justReleased for docs
Merge pull request #441 from nhowell/patch-1

Fix typo of Phaser.Key#justReleased for docs
Fix typos of method names in Button.js for docs
Fix typos in Phaser.Group#forEachExists for docs
Merge pull request #444 from nhowell/patch-1

Fix typos of method names in Button.js for docs
Merge pull request #447 from nhowell/patch-3

Fix typos in Phaser.Group#forEachExists for docs
Fix typo of Phaser.Point#setMagnitude for docs
Fix typo of Phaser.SinglePad#addCallbacks for docs

This typo was causing this method to appear in the wrong page of the docs
Merge pull request #448 from nhowell/patch-1

Fix typo of Phaser.Point#setMagnitude for docs
Merge pull request #450 from nhowell/patch-2

Fix typo of Phaser.SinglePad#addCallbacks for docs
Fix typo for Phaser.InputHandler#pointerDragged for docs
Fix typo of Phaser.Line.intersectsPoints for docs
Fix typo of Phaser.Math#fuzzyLessThan for docs
Merge pull request #451 from nhowell/patch-1

Fix typo for Phaser.InputHandler#pointerDragged for docs
Fix typo of Phaser.Graphics.prototype.destroy for docs

The method was appearing in the wrong file in the documentation
Fix typo of Phaser.BitmapText.prototype.destroy for docs
Merge pull request #455 from nhowell/patch-4

Fix typo of Phaser.BitmapText.prototype.destroy for docs