Merge pull request #763 from srazi/master

CookieManager::filterString() and some fixes from recent commits.
Revert "[QtWin] using of direct WinAPI call."

It has to be resolved at runtime to provide the same binary
compatibility with Windows versions older than Vista.

This reverts commit 2db89f50bfad33683317128dd8b8eb74c9028ac0.
Fixed hiding navigation container when disable and enabling tabs on top.

Closes #764
Don't use double QUrl::fromUserInput in QupZilla constructor.

Closes #762
Using unix line ends in COPYRIGHT.

Closes #767
Updated Polish translation for windows installer.
[SiteInfo] Use uniform item sizes in list widget.

Also fixed showing the whole item on Windows.
Preferences: Adjust size to current page on page change.
[code] Explicitly set UTF-8 codec when using QTextStream.

Fixes encoding issues on Windows.

Closes #769
[Mac] Fixed rendering of tab's buttons.
[Mac] RSSManager/AdBlockDialog documentMode was disabled and fixed double cursor problem.
Added 'MacToolButton' as a replacement for QToolButton on Mac
Moved config directory info ~/.config/qupzilla

See #774
Merge pull request #773 from srazi/Mac_work

Mac related fixes.
IconProvider: fixed, return a fallback icon on non-linux OSes
[FTP] fixed problem with 'link to file'+show shortcut icon for links