hierarchical_select 5.x-2.0-rc3

New features:
- #217395: Allow usage of operators for exposed filters
- #217368: The "" option

Improvements:
- #213703: Add a note to the README about multiple values with content_taxonomy

Bug fixes:
- Views exposed filters rearranging was broken due to a class name that has changed in HS2.
- Fix for bug introduced in fix for #215328.
- Work-around for the inability to reset the selection. (in the Taxonomy Subscriptions form)
- Fixed: the "none" item in Taxonomy selects would be selected when something was just added to the dropbox. This had no negative side-effects, but has been fixed for the sake of correctness.
- Fixed: variable was not being initialized in _hierarchical_select_reconstruct_lineages_save_lineage_enabled().
- Fixed #215328: Unselecting current taxonomy selection is not saved when "multiple select" is disabled and "save term lineage" is enabled.