(GraphicsView) Added a lot of comments;
(GraphicsView) Changed base unit from milliseconds to microseconds;
(GraphicsScrollbar) Fixed fluttering on very small scale;
(GraphicsView)+(TreeWidget) Chronometer item behavior: if selection made from left to right - selecting all items by intersection with rectangle; if selection made from right to left - selecting all items which are strictly inside selection rectangle.
(GraphicsView) Does not use standard QGraphicsView::scale and QGraphicsView::centerOn methods, does not use standard QScrollBar because of it's fast value overflow. Using manual offset for all scene items instead of standard scrolling.
* (Graphics view) Changed height of blocks. Variable thread-block height;
* (Tree widget) Disabled sorting by name to save order of threads displayed on graphics view;
* (Profiler reader) Changed type of value returned by fillTreesFromFile().
