expand advanced search only when user have checked elements in previous search
refakor _bibdk_custom_search_is_advanced_search_expanded for better test-ability
add unit test of _bibdk_custom_search_is_advanced_search_expanded
Do not expand advanced search on book and online pages
update test
Do not expand only when all materials have been chosen
test updated
Only expand advanced search pages as default or if advanced options have been used.
initialize variable
Merge branch 'feature/1027-expanded_search' into develop