Remove superseded SelectionMover.countStepsToPosition
Use cached-based conversion rather than SelectionMover.move
Remove superseded SelectionMover.isPositionWalkable
Adjust StepsTranslator behaviour

When the requested number of steps passed to convertStepsToDomPoint is
beyond the document end in, or before the start of the document, an
exception will be thrown. This closes a slight hole where asking for a
step beyond the document would return a non-step position. It also makes
the invalid usage of the interface more obvious.
Reducing usages of SelectionMover.countSteps

SelectionMover.countSteps has been replaced by step iterators and other
more performant solutions.
Remove last usages of OdtCursor.move from tests

All remaining OdtCursor tests are really testing other parts of the system that
are already covered in their own unit tests. For now, this file has been removed
and should be replaced later when OdtCursor gains additional tests.
Remove SelectionMover functions that are only used in tests

There are no worthwhile unit tests in SelectionMoverTests after these
are cleaned out, so for now the whole class file has been removed.

Mid-term, the SelectionMover class is to be removed as soon as an
implementation of navigate-by-line-boundaries has been created for
the step-iterator approach.
Merge pull request #389 from peitschie/steps-cleanup

Remove parts of the obsolete SelectionMover interface
Let the canvas's container have bouncy webkit scroll,
disable pinch-to-zoom on the editor and viewer.
Fix toolbar positioning on body scroll.

When, after clicking in the text, the iOS keyboard
pops up, the entire editor body is scrolled upwards
because the window is shrunk, even if there was
no way to scroll it before.
This means that the toolbar slides upwards and out
of the visible part of the viewport.

This is unacceptable, therefore this commit introduces
a fix:
CSS-translate the toolbar when detecting a scroll. focusout,
or touchmove event.
Toolbar polish:

* Make the toolbar absolutely positioned and full-width.
This should let it's contents properly reflow when the
screen is not wide enough.
* Add a little shadow.
Make canvasContainer dodge the overlapping toolbar.