AdBlock: Fix hiding iframes that have completely blocked contents

Closes #1552
AdBlock: Use display:block when hiding blocked iframes

visibility:hidden leaves empty space in page
Allow closing Download Manager and Browsing Library with CTRL+w
Merge pull request #1562 from oshi-shinobu/master

Allow closing Download Manager and Browsing Library with CTRL+w
Use TLS 1.2 with Qt 5 when disabling SSLv3
Windows,Qt5: Fixed compile issue.

- It fixes: error: C2308: concatenating mismatched strings Concatenating wide
- See: http://blog.qt.digia.com/blog/2014/06/13/qt-weekly-13-qstringliteral/
Show navigation bar when calling openLocation() in full screen mode.

- Closes #1464
TabBarHelper: Fix a rare bug and compute pressed index, correctly.
RTL, dir list page: Fixed position of dir-up button in RTL layout..

- CLoses #1568
Don't try to load translations for C locale