Browse: handle hiperlinks that open new windows

[manuq]

Open the ones that are wanted in a new tab, like anchors with target="_blank" attribute. Test page:

 http://dev.laptop.org/~erikos/wanted.html

And block the ones that do pop-up via javascript. Test page:

 http://dev.laptop.org/~erikos/unwanted.html

[manuq]

Looking at webview signals "new-window-policy-decision-requested" and "create-web-view", and epiphany src/ephy-window.c which have callbacks for them.

[manuq]

Patch sent to the mailing list. Both test cases pass.

Please pay attention to the patch comment regarding the "reason", shall we do any exception, that is, any new window request that should be blocked?

Here is a list of all the reasons:

 http://webkitgtk.org/reference/webkitgtk/1.8.0/WebKitWebNavigationAction.html#WebKitWebNavigationReason

[manuq]

We may also find useful this signals the WebView provides: script-alert, script-confirm, script-prompt. Maybe catch them and use our Sugar Alert instead of pop-ups?

[manuq]

Pushed as 022ef0dd9791af51d7b9de38e813096f2ca60948 .