 Removes forced hardware acceleration on minimap

With the new view-aware rendering of the minimap a lot of time is now
passed refreshing the gpu textures when new lines are added/removed
during scroll. Using the profiling tools confirm that.

This commit includes removal of all the `accelerated` class inclusion
in container node and put it instead on lines.
It also includes the change of the translate method to generate
`translate` transformation instead of `translate3d`.

This is an experiment, on my MBA I can feel that scrolling is a little bit smoother (less lag when the minimap is updated), but I can be wrong. The profiler seems confirming that a lot more time is passed in updating the wrapper element when scroll trigger a changes of the rendered lines.
I'll need more feedback to definitely consider these changes as a real improvement.