[WebView] Added option to force context menu to be opened on mouse release

This is needed for mouse gestures to be able to use right mouse button.
See #1280
[Coding Style] Edited coding style (use linux style brackets)

Linux style brackets are now used also for source files.
One line blocks can now be without brackets.

Example:

if (test)
    foo();

Multi-line if statements are now written with conditionals (||, &&, ...)
at the end of line. The last line of if body does not ends with closing
bracket, instead the closing bracket is written on separate line.
One line blocks in multi-line if statements should not be without brackets.

Example:

if (test ||
    test2 &&
    test3
   ) {
    foo();
}

[ci skip]
[MouseGestures] Implement "Rocker navigation"

Left+Right click - Forward
Right+Left click - Back

It is currently disabled by default and there is no GUI to enable it.
[MouseGestures] Configurable mouse gesture button

UI changes:
* the Settings dialog offers a combo box to select left and right
  mouse buttons, or disable the gestures completely
* changes are permanently saved
* OK button is added

Closes #386
Closes #1280

It is now also possible to enable/disable rocker navigation.

Closes #1234
[MouseGestures] Bump plugin version

[ci skip]
[AdBlock] Improved performance of loading rules

Don't use regexps for parsing rules.
Added benchmark for loading subscriptions

Before:

********* Start testing of AdBlockParseRule *********
Config: Using QTest library 4.8.6, Qt 4.8.6
PASS   : AdBlockParseRule::initTestCase()
RESULT : AdBlockParseRule::parseEasyList():
     596.3 msecs per iteration (total: 2,982, iterations: 5)
PASS   : AdBlockParseRule::parseEasyList()
PASS   : AdBlockParseRule::cleanupTestCase()
Totals: 3 passed, 0 failed, 0 skipped
********* Finished testing of AdBlockParseRule *********

After:

********* Start testing of AdBlockParseRule *********
Config: Using QTest library 4.8.6, Qt 4.8.6
PASS   : AdBlockParseRule::initTestCase()
RESULT : AdBlockParseRule::parseEasyList():
     481.8 msecs per iteration (total: 2,409, iterations: 5)
PASS   : AdBlockParseRule::parseEasyList()
PASS   : AdBlockParseRule::cleanupTestCase()
Totals: 3 passed, 0 failed, 0 skipped
********* Finished testing of AdBlockParseRule *********
[Build] Fixed building with Qt5
[Windows] Fixed compile issues after aa248893 and  7f3d8ee7
[PageFormCompleter] Try to be extra cautious with QWebFrames

This is an attempt to fix crash when calling QWebFrame::childFrames
in PageFormCompleter::getAllElementsFromPage

[ci skip]
Fixed build after 39c9fec3dd