antanym 0.4.0

General revisions following rOpenSci review. Note several breaking changes:

an_read now takes a cache parameter instead of cache_directory (and now can have special values "session" and "persistent")
an_filter and an_suggest now take an origin parameter that replaces the previous origin_country and cga_source parameters
the default data structure (returned by an_read(..., simplified = TRUE) no longer contains the "country_name" or "cga_source_gazetteer columns, but if needed these are available via an_read(..., simplified = FALSE)

antanym 0.3.0