bugfixes: click the same tag and loading tags.

- clicking on the same tag more than once has no effect.
- previous tags disappear, and "loading tags..." message is shown.
artist's id being used to get tags.

echonest limits requests to 120/min.
requests are cached, but this is not enough.
albums not showing bug fixed.

all albums were returning false on "playable" property.
max tags for artistmenu refactored
tags centered
events tweaks
box menu style removed
refactoring and docs added
models.ArtistGraph documented
DOI badge added
Components docs added.
controller docs updated
Controller docs updated
exceptions not being used. file discarded
more refactoring: header controllet not needed
afterLoad refactoring
refactoring controller initialization
controller initialization refactoring done.
refactoring settings. bugfix on graph creation
refactoring graphcontroller