Move view->id to view->ops->id
Add struct view_env for storing shared state between views
Add title window field to struct view and move window declarations
Move apply_step to tig header
Move display and status code to new display module
Move common view code to view module
Move view parsing code to new parse module
Move pager core to new pager module
Move log view to new log module
Move diff view to new diff module
Move help view to new help module
Move tree view to new tree module
Move blob view to new blob module
Move blame view to new blame module
Move branch view to new branch module
Move status view to new status module
Move stage view to new stage module
Move main view to new main module
Move stash view to new stash module
Remove view_ops define and #include view backend header files