Browser - Sometimes Reload button does not work after clicking

Browser - Sometimes Reload button does not work after clicking
Stop button

[Issue]        https://bugs.tizen.org/jira/browse/TT-173
[Problem]      Sometimes Reload button does not work after clicking
               Stop button
[Solution]     Stop button created loadFinished signal, to solve this
               loadStopped was created. In  addition, engine was still
               sending __loadProgress signal, which I blocked after
               Stop button was clicked. As you can not get title and
               snapshot from unloaded page, it was exchanged by blank
               image and url for view and for history manager.
[Verification] Open new page and stop load. Page should not load any
               additional content. Reload and enter button on url
               should force webview to refresh.

Change-Id: I5bdab33254ff8dd0ef5302443b21fd23ed82f661