Problems with csv export

[dima4p]

Environment

• Ruby 2.6.3
• Rails 5.2.3
• WiceGrid 4.1.0

Description of issue

1. After I have enabled in initialize_grid the option enable_export_to_csv it turns out that the file page_white_excel.png is missing.
2. Turbolinks are not disabled while rendering export csv.

Current behaviour

1. the file page_white_excel.png is missing.
2. the csv file replaces the page and only after I reload the page the browser offers me to save the file or open with office.

Expected behaviour

1. It should be either in the gem or in "Font Awesome"
2. the browser should offer me to save the file or open with office immediately without changing the current page. For that the button click should first disable turbolinks

Additional context

I have to use temporary it from my old projects. Additionally from there were two unneeded files requested: table.png and table-refresh.png, that were added to buttons "Filter" and "Reset". Without them there were 'routing error'

[VignetteApril]

I currently meet this problem either, hopefully @patricklindsay can accept the commit from @dima4p