readme: Add formatting sugar for readibility

* Added a bit more formatting for UNIX-like systems dependencies installation.
Merge pull request #2243 from mrshu/patch-1

readme: Add formatting sugar for readibility
Add support for npm 2
Merge pull request #2249 from Gared/support_npm2

Add support for npm 2
If exportFileName hook isn’t defined don’t return empty filename.

This commit should fix #2251.

If ``exportFileName`` hook is not defined, ``hookFileName`` should be an empty array. Test the length of ``hookFileName`` before overriding ``fileName``, the export filename.
Merge pull request #2252 from otetard/bugfix/fix_export_filename

If exportFileName hook isn’t defined don’t return empty filename.
Fix active button ui
Fix import/export popup margin @ timeslider
Merge pull request #2256 from 0ip/develop

Fix active button UI, when a popup is shown
Fix user count
Still dirty, but really works.
Prevent selection on buttons
Merge pull request #2258 from 0ip/fix/button-select

Prevent selection on buttons
Merge pull request #2257 from 0ip/fix/user-count

Fix broken user count
Localisation updates from https://translatewiki.net.
escape useragent before displaying
I prefer this..
Merge pull request #2261 from ether/fix-xss-on-useragent

Fix xss on useragent
Move `title` attribute of buttons from `<span>` to `<a>`

The `.toolbar ul li a` that holds the `span.button` has a
padding of `4px 5px`. This means if the mouse is on the edge
of the button the `:hover` state is active but the relevant
tooltip does not show up. Moving the `title` attribute to
the `<a>` itself solves this problem.

Also removed some extra whitespace.
Add 'Ctrl-5' keyboard shortcut for 'strikethrough' #1987

A quick search revealed that 'Ctrl-5' is a popular shortcut
for strikethrough. Implemented in 'ace2_inner' and updated
the English l10n file for the tooltip.
Merge pull request #2265 from prtksxna/keyboard-shortcut

Add 'Ctrl-5' keyboard shortcut for 'strikethrough' #1987