Several wxWebKitCtrl enhancements/fixes. Including:

Several wxWebKitCtrl enhancements/fixes. Including:

- new methods for increasing/decreasing text size, getting selection, getting/setting scroll position, printing, enabling editing, and running JavaScripts on the page.

- added new event (wxWebKitBeforeLoadEvent) for catching, and possibly vetoing, load events before they occur.

- wxWebKitCtrl now fires mouse events for certain events that it was eating before. This improves wxSplitterWindow resizing behavior.

- refactoring of the sizing logic to move the Cocoa view. I've tested this with splitter windows, panels, notebooks and all position correctly with this.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@42107 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775