Update TypeScript definitions

Made the "index" parameter optional to reflect the JS version.
Documentation updates.
Added an additional tile index check to P2.World.convertTilemap.
Moved the this._reversed flag outside of the property loop in Tween (as per tween.js issue 115)
Emitter.makeParticles updated to use Array.isArray() check on the key/frame values, so non-string objects can be passed in (thanks @AnderbergE, fix #786)
Doc updates.
Fix Phaser.Line.intersectsPoints by properly checking the boundaries
Tilemap.createFromObjects will now force the creation of the property again even if it doesn't exist (regression fix from 2.0.4)
New `force` parameter added to Group.set, setAll, setAllChildren, setProperty which controls if a property is created even if it doesn't exist.
Group.hasProperty will check a child for the given property and return a boolean.
Readme updates.
Merge pull request #790 from woutercommandeur/dev

Fix Phaser.Line.intersectsPoints by properly checking the boundaries
Merge pull request #787 from luispedrofonseca/master

Updated TypeScript definitions