Add the actions UndoTabClose, BookmarkNew, SaveAs, SourceView and Print
to the context menu. Also add UndoTabClose to the Go menu, remove
STOCK_SOURCE_VIEW and remove ui.h which is obsolete.
The 'browser' struct is superseded by MidoriBrowser, which actually
represents a window that holds pages, i.e. tabs. The tabs are currently
of the type MidoriWebView, which is a slightly enhanced WebView. Also
MidoriWebSettings is introduced to hold additional settings that Midori
needs.
The other two new classes are MidoriTrash, representing closed tabs and
windows and MidoriPanel, representing the side panel.
The refactoring allows for several features to be much more easily
implemented, such as full support for multiple windows and instant
saving of modified files, such as bookmarks or the session. Regressions
are expected and not everything is done yet.
