daemon: fix loss of data when handling input lines from clients.

This was happening because Voiceman does not decode utf-8 sequences crossing
the block boundary.  In such a case next block would start with bad utf-8
sequence and Voiceman would lose all data from that block.  This includes
all newline characters in this next block, so subsequent commands would be
lost as well.

This patch fixes the problem by handling input lines in utf-8, without
decoding them to wstring beforehand.
Default configuration fix:
- maximum input line length is relaxed since it is measured in bytes instead of characters.
Merging new fixes from 1.5 related to an incorrect UTF-8 processing
daemon: produce beep at the point of input line truncation.
ChangeLog update for coming 1.5.1 release
Merging ChangeLog fixes from 1.5