fixed collision test example
fixed documentation, as this function never returns a me.Rect object
[#538] only execute the built-in function if not explicitly returning false
[#539] preliminary multi-shape support
[#539] fixed various index not being properly cleared/used

fully working now !
[#539] removed the temporary additional shape in the example
[#539] added documentation for the new response object properties
[#539] added a bunch of utility function to remove shapes

also the `shapes` array is now private, and end-user must used the
provided add/remove function to manage them.
Merge branch 'ticket-539'
CHANGELOG update
Added collision detection for `me.Line` shapes

this works out of the box with the current SAT algorithm !
oups !
added user agent detection for Kindle devices, and also set `isMobile` accordingly (untested!)

@see http://amazonsilk.wordpress.com/useful-bits/silk-user-agent/
[#569] Fix debug drawing for me.Line objects
Fix enemy collisions in platformer

- onCollision MUST now return false for "no response"; return undefined is not enough
- See: https://github.com/melonjs/melonJS/commit/41540435262c23c17705418046c943fac7712480
[#569] Convert all platform shapes in Platformer example to PolyLines

- This demonstrates a bug with setting the inViewport flag on me.Line, which may potentially have its height OR width === 0.
[#569] Fix the disappearing platforms

- Affects world entities created with TMX polygon/polyline (neither entity is given a width or height)
- Fix is to check inViewport using the entity bounds instead of the entity geometry
- It's still unclear if we want to keep the bounding box separate from the entity (which is already a rect)
[#569] Optimize me.Line and collision checks.

- 90% of me.Line was removed! Now inherits from me.Polygon
- Small optimizations in collision checks, especially me.collision.testPolygonPolygon no longer needs to compare the normals on a me.Line twice
Remove bower from the npm `install` command
[#569] Add support for initializing `me.Body` with a default list of shapes

- Makes `me.TMXObject.getShape` a private method, renames it to `getTMXShapes`, and returns an array
- `me.Entity` now initializes its body with a list of shapes using the private `settings.getTMXShapes` method