message.rb: make sure [] chunks warning is returned when message is not loaded
test: bad or binary content transfer encodings
test: rename test_messages to test_messages_dir
Revert "Merge #189: Added hidden_alternates config option"

This reverts commit 34287a219b559303fb99cc9b54673171f84702eb.
Merge #204: Revert hidden_alternates option.
prepare for release 0.15.3
lib/sup: dont close log_io if nil/false
ncurses: move all references from Curses to Ncurses
ncursesw: COLOR_PAIR beats color_pair
textfield: dont try to set cursed value to nil
bounce: use first element of array for sensible bounce question