viewer.properties - Polish lang : sync with English file and translated new values

I merged Polish viewer.properties into English file (only these lines that have equivalents in English file) and I translated lines wasn't earlier in Polish file.

I only wasn't sure if "Web fonts"="Web fonty" in Polish and if I translated properly "web_fonts_disabled" .

removed values:
error_build
loading
toggle_slider.title
toggle_slider_label

added values:
toggle_sidebar.title
toggle_sidebar_label
presentation_mode.title
presentation_mode_label
open_file_label
findbar.title
findbar_label
thumb_page_title
thumb_page_canvas
first_page.label
last_page.label
page_rotate_cw.label
page_rotate_ccw.label
find_label
find_previous.title
find_previous_label
find_next.title
find_next_label
find_highlight
find_match_case_label
find_reached_top
find_reached_bottom
find_not_found
invalid_file_error
missing_file_error
request_password
printing_not_supported
web_fonts_disabled