fix page-up/down in 'tog ref' view; ok naddy

fix page-down/page-up scrolling in the tog tree view problem reported by, fixed with lots of help from, and ok naddy

tog: make it possible to open a ref view from the tree view

fix entry selection when moving to the parent in tog's tree view The tree view attempts to keep the scroll position of an already visited parent directory intact. If we start out by viewing a subtree and then move up, the scroll position of the parent isn't actually available since the parent tree was never nagivated by the user. In this case tree_view_walk_path() has to fill in some values. The only parent entry we know about in this case is the one which was traversed to reach the child. The best we can do is to lock the parent's scroll position such that the traversed child entry appears at the top of the list if moving up to the parent's view. If we then navigate down again and return, the parent's scroll position will start to be retained and restored properly. Analysis and draft patch by stsp, initial report and simpler fix by yours truly. ok stsp

let tog's tree and ref commands call their own usage() and not each other's

support opening a tree view from the ref view; requested by naddy

trigger log thread if a log view is opened as a child view; found by naddy

fix calls to ref_usage(); found by naddy

initial 'tog ref' implementation ok naddy tracey

store reflists in view state where required and get rid of reflist pointers ok tracey naddy

make 'tog diff' accept reference and tag arguments; add -w and -C options ok naddy tracey

reset tog diff view's scroll position if diff context shrinks too much

handle binary files in got/tog diff commands; add -a options to force text

fix type of filesize output parameter of got_object_blob_dump_to_file()

remove now pointless 'check_disk' parameter of got_repo_map_path() suggested by naddy