have pattern always as unicode and normalized
take care about path - unicode handling

convert sources to unicode and normalize it as soon as possible
decode to utf-8 and normalize plugins path
errors from plugins are not raised by p.error
decode exec arguments to utf-8
decode to utf-8 and normalize excluded_path
info about utf-8 to changelog
moved *prepare_execute* functions up in code
pylint: disable too-many-branches, too-many-statements for parse_input_args