Group - 'iterate' documentation and guard

Update iterate documentation to cover usage of `args` and added a guard so
that the callback can be used without requiring that `args` is specified.

Ref. https://github.com/photonstorm/phaser/issues/1352
Group - additional documentation refinement

General tidying/corrections of Group documentation.
Merge pull request #1373 from clark-stevenson/dev

Small Updates
readme update.
Phaser 2.2.0-RC12 Release
Time/Time - documentation updates and minor cleanup

- Removed `Time.pausedTime`

  Time.pausedTime has not been used / updated since
  b255fea85f7b4bb9b0a335a1407300db83e3f671 in Feb 2014.

  There might be a case to re-explore how pause time is
  reported/observable, possibly with a distinction of 'current' and 'last'
  and the semantics of such. For instance, pause duration is only updated
  after the resume occurs and reflects the duration-of-the-last-pause..

- Removed `Time` _i and _len properties These are better suited by local
  variables.

- General documentation updates.

- Marked several methods such as `Timer.order` as protected - there are
  advanced use-cases for them, but different user-facing methods and
  documentations are likely in order. Also marked `Timer.sortHandler` as
  private; but did not change any interfaces.
TimerEvent - tabs to spaces

Converted tabs to spaces, for consistency
Merge pull request #1374 from pnstickne/wip-time-quibs

Time/Time - documentation updates and minor cleanup
Minor logic fix for Sprite life update

The substraction of `physicsElapsedMS` needs to be done for all individual
updates. (When current FPS ~ target FPS this is a 1-1 mapping, but catchup
updates can throw off the calculations.)

Also renamed `Game#updateNumber` (a poor initial name on my part) to
`currentUpdateID`. This matches the naming of
`Stage#currentRenderOrderID`.
jsdoc update
Added optional 'no physics' flags.
Added alpha setting to getContext.
Small defs fix.
Sprite - removed comment

The comment was no longer valid after the previos changes.
jsdoc - PIXI documentation filtering

Added the filterpixi.js jsdoc plugin which marks some PIXI
interaction-related methods and properties as private. This ensures that
they do not show up in the final Phaser documentation.
jsdoc - added namealias

The namealias plugin gets jsdoc to detect lots of documentation it was not
correctly picking up due to the application of the `name` property. This
can be read about in
https://github.com/jsdoc3/jsdoc/issues/804#event-195287680 - this results
in _much_ more complete documentation generation, especially when
properties are defined in constructors.
jsdoc - short/friendly @link plugin

Added support for short `{@link #member}` markup. This makes interlinking
much cleaner and shorter; similar short-link support was available in
previous versions of jsdoc.
jsdoc - sourceproxy docs and cleanup
jsdoc - namealias fix

Fixed issue with namealias and class doclects without names.
Documentation - general

Updated some documentation for formatting, consistency, and minor
corrections.