[Preferences] add option to set Ctrl-Q behaviour (Quit or nothing)

Motivated by #695 which targets broader task, Ctrl-Q behaviour is one
that stands out. Accidentally pressing it instead of Ctrl-W can have
disasterous consequences or is annoying. Other browsers provide either
generic keyboard shortcuts configuration (Opera) or an extension/plugin
to disable the behaviour (FF).

For the record of the usability demand:
https://code.google.com/p/chromium/issues/detail?id=59621
https://bugzilla.mozilla.org/show_bug.cgi?id=550559
Refactor encoding menu creation

* Use of codec MIBs instead of names significantly decreases
  number of iterations
* Remove duplicated codecs
* Fix memory leaks which were caused by wrong parenting and
  empty menus
* Do not add separator if menu is empty
use svg instead of png for CI build status icon to get better quality
Merge pull request #1433 from PeterDaveHello/patch-1

use svg instead of png for CI build status icon to get better quality
Merge pull request #1432 from trollixx/encoding

Refactor encoding menu creation
Merge pull request #1431 from kdave/preferences-ctrl-q

[Preferences] add option to set Ctrl-Q behaviour (Quit or nothing)
fix linking on qmake installations that use compile_libtool.
Merge pull request #1441 from niclasr/master

fix linking on qmake installations that use compile_libtool.
Unix: Use /tmp/qupzilla-$USER as temp path

It makes it possible to run QupZilla on more accounts at the same time
Fix typo
Merge pull request #1453 from marclaporte/patch-1

Fix typos
AdBlock: Reload global user stylesheet after disabling/enabling AdBlock

It was needed to restart the browser to completely disable / enable
AdBlock.
AdBlock: Add support for parsing CSS Element hiding exceptions

Those rules are however not supported at the moment.
AdBlock: Add support for exception css rules

Closes #1446
AdBlockRule: Add copy() method

Faster method to copy rule than parse again the filter.
Plugins: Use settings path without trailing slash
GreaseMonkey: Use openuserjs.org instead of dead userscripts.org
GreaseMonkey: Correctly run scripts in frames

Closes #1457
GreaseMonkey: Run scripts on DOMContentLoaded event capture

Fixes second part of  #1457 (not working on settings, identities, ..
pages)
PageScreen: Use Save dialog instead of Open dialog

[ci-skip]

Closes #1454