Merge pull request #114 from jrouviere/canvas_rendering

Redraw minimum number of lines + Correct indicator drag behaviour
:bug: Fix smooth scrolling issue with visible area

As discovered by @jrouviere the callback `minimap:updated` was the
cause of the stop
before the edges.
After removing it the minimap lack a proper placement because it is
initialized before the tabs view affect the layout.
To solve that a mutation observer is created on the pane
and the minimap is relocated whenever children are added to or removed
from the pane view.
Finally the two layers surrounding the editor scroll at the same time
than the minimap.
:bug: Fix scrolling and dragging off for large file before rerender

The callback to `minimap:updated` is required for when
the minimap editor view size changes due to an update.
Add a mixing to offer the same API for decorations as editors
Include decoration mixin in minimap editor view
Delegate decoration method on the minimap view
Adapt event dispatching to the view syntax
:bug: Fix typo in require
:racehorse: Remove query when accessing the dummy node
Extract reading dom and creating dummy in specific methods
First plug of the decorations up to the drawLines method
Change row index for the decoration dummy code
Implement drawing line decorations in the minimap
Add highlight decoration rendering
Add changes on decoration creation/deletion/update
Remove dummy code to test decoration
:bug: Fix invalid range access on display buffer markers
:guardsman: Protect against errors in findMatchers with NaN endRow
Ignore .live-archive
Use requestAnimationFrame instead of setImmediate

It limits the amount of update per frame and seems to fix
the error raised when finding markers.
It also seems to fix a lot of weird behaviour when decorations are
added to the minimap.