TilemapLayer / Tileset performance and documentation

TilemapLayer
 - Added "delta scroll rendering"
   - Enabled (by default) via `renderSettings.enableScrollDelta`
   - Dramatic CPU reduction: 30% to 2% scrolling 50x37 region
   - Side-effect: fixed some Chrome de-opt issues with `render`
   - Various rendering updates and removal of many `_mc` field
 - Made `index` a read-only propert that reflects the layer.index
 - Creates a local cache from tile index -> tileset, added `resetTilesetCache`
   - Also prevents crash when an index not associated with a tileset is
     used; see `missingImageOverfill`.
 - Various debug options moved to `debugSettings` and simplified; documentation updated.
   - Uses `debugSettings.missingImageOverfill` and `tileColor` (deprecated) to display invalid tileset images
 - Only change the context alpha when the tile alpha changes; in Chrome 38
   this removed a .5% penalty
 - Added `renderSettings` which controls misc. rendering/optimizations.
 - Updated documentation to @member, clarified

Tileset
 - Added `containsTileIndex` method to allow being queried if the specific tile index is handled/supported.
 - Uses a firstgid bias and interlacing to fit the data in single densely packed array.
 - Updated documentation to @member, clarified
Merge branch 'dev' of https://github.com/photonstorm/phaser into wip-tilelayer
TilemapLayer / Tileset

- Minor regression fix, increasing argument specifity/documentation
TilemapLayer / Tileset documentation to Phaser conventions

- Reverted @member to @property for uniformity
- Expanded some comments
Button - bug fixes, issue #1246

  - Fix incorrect passing of "was clicked" to processInteractiveObjects
  - Button would not return to Over/Out state because of strict too check to catch `undefined`
  - Removed [undocumented] property usage from processInteractiveObjects and slight reformatting
  - Update Button state frames/sounds to remove duplication
  - Updated documentation in Button for consistency
Merge remote-tracking branch 'upstream/dev' into wip-1246b
Changes to preserve original API

- Added @deprecated/@readonly to various some properties but public properties maintain the same semantics
- Also removed some "cleverness"
- Still same good fixes ..
TilemapLayer/Tileset - Documentation consistency updates for Phaser
Browser incompatibility fix - MAX_SAFE_INTEGER

- Number.MAX_SAFE_INTEGER is only defined in ES6 and not currently cross-browser
Added "property to member" plugin for JSDoc

This automatically fixes usage of the form

    /** desc
    * @property {T} name - desc

To

    /** desc
    * @member {T} name

Being careful to only make the transformation when it is logical to do and preserving both descriptions as appropriate.
JSDoc Property to member - slight combining update
PIXI-in-Docs - Initial

- Initial support for generating PIXI-combined documentation
- Includes yuidoc-to-jsdoc for generating pixi-jsdoc.js
- Creates doc (using pixidoc + builddoc) tasks
- Adds sourceproxy JSDoc plugin to map in corrected file/line meta
- Added yuidocjs as a dev-dependency
PIXI-in-Docs - making jshint happy
PIXI-in-Docs fixups

- Removed hard-coded path (oops)
- Added grunt task (oops)
- Added EOLs
PIXI-in-Docs: prop support

- Added support for nested/ad-hoc properties
- Also cleanup and documentation / limitation notions
PIXI-in-Docs: visibility fix

- Private methods were not being annotated as such
PIXI-in-Docs: fixed line numbers

- Also added support for various additional meta-tags
- Minor code cleanup
Merge pull request #1272 from pnstickne/wip-1246b

Button - bug fixes, issue #1246 (try number two)
Merge pull request #1287 from pnstickne/wip-props-to-members

Docs: PIXI Integration and "property to member" decorator for JSDoc
Small jsdoc fixes.