Doc: Added link to SQL example page from main Qt SQL landing page.

Change-Id: I1fe42b6ec72933ea8ba605836e8a56332fd3c691
Reviewed-by: Martin Smith <martin.smith@digia.com>
Windows: Added Comma to list of possible numpad keys

Some keyboard layouts (German and Czech for example) have comma instead
of period on the numpad, so this key should also be considered when
setting the Qt::KeypadModifer state.

Task-number: QTBUG-38248
Change-Id: I06847a02a9334c21784790eae6fd7e1bc6de4099
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
winrt: do not try to close non existent sockets

Change-Id: I41103db89985f8fbde1faaccaf33c7a76c275f7d
Reviewed-by: Andrew Knight <andrew.knight@digia.com>
winrt: set error if tcp socket initialization fails

Change-Id: I31a2684ffdc864c69fe896829bca860e88c4a6ca
Reviewed-by: Andrew Knight <andrew.knight@digia.com>