Added batch-deletion support + VS2012 upgrade

- The history view now allows multiple images to be selected. These
images can then be deleted all at once with a single press of a button.
- Upgraded solution and project files to Visual Studio 2012
- Added some additional catch statements to some code
- Added a button to open a history item's link in the browser
- Added some clickable links instead of them being plain text
- Added some links to the About view, as well as a fancy logo