Status bar feature with current row count - way simpler EDA

[sebastianrothbucher]

small addition to get a statusbar when running with show_statusbar=True. It shows the number of rows currently available - which helps a lot with exploring a dataset (EDA), e.g. when setting a filter and getting an idea about the percentage of the full data matching an additional criterion. Example: have a sales data set, see 1M rows, set filter for "Europe", see 200k rows. plus: avoid layout issues in new grid or jquery (write <i></i> instead of <i /> which is misinterpreted)