[documentation] fixed missing inherited properties for `me.ColorLayer` and `me.ImageLayer`

also removed the overwritten update function, since we do not change
anything compared to the original `me.Renderable` one.
[documentation] fixed given `me.event.subscribe` KEYDOWN and KEYUP examples
small update to the trimming functions and added a corresponding test unit.
Merged the drag'n'drop unit test into the "official one"

Not really sure what I did is 100% right, but so far it seems to be
working ;p
fixed the camera tweens (for fadeIn/Out) not being properly de-allocated

Those ones were allocated through the entityPool
[#266] allocated `me.Color` "on demand" for the fadeIn/Out effect through the object pool functions
[debug] fixed the update time in the debug panel

it would be nice to draw a graph for this as well and show as
percentage how much of a frame is used for both updating and drawing
objects
Simplified the main loop management by calling directly me.game.update (slightly modified) and me.game.draw from the RAF callback

this also nicely cleaning the debugPanel code :P
small fix following the previous commit
[#266] fixed an issue when applying the TMX `trans` property
fixed the `move` function when checking for the camera bounds
[examples] fixed the old basic tiled loader
[#99] added a polyfill for `performance.now`

this is way more simple than the previous code with the `highRestTimer`
support flag
[#99] object update function now provide the time elapsed since the last update

Except for the `me.game.update()`, since it's the main entry point for
the RAF callback, and `me.Timer.update()` since the delta is calculated
there first.
merged in 1.0