core: fix display of bar item "buffer_filter" when toggling filters in current buffer (closes #150)
core: use argument "-i" for sed command (don't create a temporary file)
core: fix build with autotools and gettext >= 0.19
Version 1.0-rc2
update polish docs
Revert "core: use argument "-i" for sed command (don't create a temporary file)"

This reverts commit b2466aae296dd5c20612f409c2c85bfd808acac2.

The option "-i" is not supported on FreeBSD.
doc: remove trailing whitespace in Polish user's guide
core: display warning on $TERM only if it doesn't start with "screen" (under screen/tmux)