Fixes in multitouch example

- Fix #debug
- Move the `return false` for event propagation to the correct callback.
Fixed PointerEvent feature detection on un-prexifed implementation
do not redefine `Event.pointerId` on platforms supporting `PointerEvent`

In case of PointerEvent implementation, and with one event fired at a
time, the property will be (already) defined anyway.
fixed the multitouch html
Changed the default value for the throttling feature and also disabled it if the the default resolution time is smaller or equal to 16ms

also added a public `me.input.throttlingInterval` that can be changed by
the end-user
Updated the debugPanel minimum version requirement

folllowing last update with the `registerPointerEvent` function call
oups ! forgot to remove this before committing :)
[#230] BitmapFont: Fix drawing characters whose charCode is < BitmapFont.firstChar
[#230] Fix that also increments `x`
Fixed test on PointerEvent support
Fixed an initialization issue when running under MS Visual Studio 2012

This seems to only happen under MSVS2012, when not using the pre-loader.
Renamed and simplified melonJS specific properties in Event object

see discussion @
https://github.com/melonjs/melonJS/commit/dd15594b41b0e272717815701a35e10e4a16a592
Add "Mobile" to `me.sys.isMobile` UA sniffer (Firefox OS)

Mozilla/5.0 (Mobile; rv:18.0) Gecko/18.0 Firefox/18.0
Fixed throttling interval (dynamic) value not being taken in account

that seems to fix the behavior when lowering the fps rate, and as far as
I can tell is giving the same result (tested using the multitouch
example, by lowering the fps rate to 30, and then testing by
enabling/disabling event throttling)
[#229] added a `screenToWorld` and `worldToScreen` function

also used it from me.input when converting coordinates
attempt at documenting the new `gameX/gameY` properties :)
Fix Platformer example maps (for Tiled)
Fix touch input coordinates when the page is scrolled.

- `getBoundingClientRect` returns a rectangle that is relative to the viewport. See: https://developer.mozilla.org/en-US/docs/Web/API/element.getBoundingClientRect#Returns
- The cached canvas location must be updated when the viewport is scrolled
- Also add a new `WINDOW_ONSCROLL` event for minpubsub

This bug was discovered when enabling the debugPanel in the platformer example; Load the game, scroll the page down (E.g. align the top of the canvas to the top of the browser viewport). Try to click the debug options. Also try with different scroll positions near the original scroll position (0,0).
Documentation fixes.
More documentation changes.