Add italian translation, under MIT license
Merge pull request #538 from frafra/master

Add italian translation, under MIT license
Suppress manual task processing to prevent skewing of benchmark figures

Manually processing the redraw tasks vastly affects the current benchmark
results, dwarfing impacts from most other subsystems. Disabling this for
now to aid tuning of non-UI components.
Merge pull request #593 from peitschie/benchmark-tweak

Suppress manual task processing to prevent skewing of benchmark figures
Extract common concept for retrieving text content associated with a step
Re-align downgrade whitespace logic to match upgrade whitespace

Downgrade whitespace now follows the same logic as upgrade, and will
downgrade a whitespace element just to the left of the step, and to the
left of the next step to the right.

Using step iterators instead of position iterators also fixes some failing
operation tests by ensuring one step to the right is checked irrespective
of how many positions there are between steps.
Merge pull request #570 from peitschie/downgrade-fix

Re-align downgrade whitespace logic to match upgrade whitespace
Disable running tests with Rhino.
Rhino runtime lacks (wrappers for) essential necessities such as Uint8Array,
Node and NodeFilter.
Merge pull request #579 from vandenoever/disablerhino

Disable running tests with Rhino.
Add about dialog to editor component
Merge pull request #465 from kossebau/addEditorAboutDialog

Add about dialog to editor component
Make canvas overflow hidden.

Even though the sizer is scaled, it's original 'ghost'
size is used to hint scrollbars in Firefox (unlike in Chrome).
Therefore the canvas's overflow needs to be hidden to
prevent this ghost size leak.
Re-apply inline-block to canvas element on resizing.
Chrome tends to forget this property after a relayout.
Do not show a scrollbar in slideshows in the viewer.
Slideshows are (currently) meant to be navigated by
the nav buttons.
Let sizer overflow out of the canvas during
a pinch-zoom gesture.
Center all slideshow pages
Move slideshow CSS customizations for canvasContainer to viewer.css
Apply presentation mode styling via classList.add,
and not by setting the className.
Merge pull request #589 from adityab/scrollfix

Polish and papercut-fixes for the viewer
Make caret and avatar overlays rather than inline content

Having the caret and avatar display inside the cursor node causes text
wrapping and other element shifts to occur in some browsers (mainly FF)
due to there being layout impacts from the almost-but-not-quite 0-width
cursor element.

Moving to non-inline overlays for these bits of chrome allows the cursor
to be hidden completely.

TODO
This commit introduces a regression when composing text using an IME
as the overlay doesn't advance properly during composition.

Fixes #86