Adds Debug mixin in MinimapView too
Moves miniScrollView affectation

There’s no reason the minimap scroll view changes over time as we
changes its content. We can store it once after creation.
Removes attach method

The name was confusing, nothing was attached in the DOM.
The code belonging to attach is now part of the constructor.
Style changes

Makes the code a bit more coffee script friendly
Extracts activation and deactivation in specialized methods

It’ll be useful in incoming commits
Renames getActiveEditor as storeActiveEditor

The purpose of the change should be obvious here as
`getActiveEditor` wasn’t actually used to retrieve the editor.
Replaces call to getActiveEditor

The indent is messed up, waits for the next commits for details.
Adds methods to test the active tab and minimap presence
Implements a cleaner way to deal with invalid tabs

A test is performed directly in the `onActiveMinimapView` callback, the
minimap is then removed on non editor tabs.
Adds an update of the minimap width when attached