Update instructions for offline_message.
Remove api module from core modules list, no longer relevant. Remove old commented out code block.
Improve documentation on hook_assemble_form_state_into_field(). Remove drupalgap.api, _drupalgap_api_get_csrf_token(), drupalgap_api_default_options() and hook_field_data_string(), they have been long deprecated.
#284. Change _drupalgap_form_state_values_assemble_get_element_value() to handle list_boolean. Change _drupalgap_form_render_element() to use the item's value, if it exists, as the variables.attributes.value instead of always using the default value.
#284. Change drupalgap_entity_build_from_form_state() to use the field_key.value as the key if possible, and to properly push the field_value onto a field when not using a delta and not using a wrapper from hook_assemble_form_state_into_field() implementations.
#284. Change list_field_formatter_view() to handle list_boolean with options_onoff. Add list_assemble_form_state_into_field(). Remove options_field_data_string(), it has been long deprecated. Change options_field_widget_form() to handle list_boolean with options_onoff.
Remove drupalgap.services.rss, it has been long deprecated.
Update binary.