Revert "IMAP: defer bailout in case of EOF"

This reverts commit afb1d1949e7bb9849e0fe33e4d3ae971711337bd.
Fixed long (>255) utf8 headers + unit-test
Added validation of invalid utf8 sequences (replacing invalid char with "?") + unit-test
Merge branch 'dbmail_3_1_utf8_fix' of https://github.com/alyarskiy/dbmail into dbmail_3_1
fix unit-tests after merge
boundary fix for sha512 passwords #1040
support wrapped boundaries during reconstruction
remove unused file
IMAP: EOF on stdin is not an error
POP3: fix segfault; fixes bug #1043
LMTP/TIMSIEVE: fix possible segfaults
IMAP: fix inverted logic during abort
fix regression in utf7 mailbox matching
Fixed wrong result check in change username function.
IMAP: add loop protection to cleanup callback
version 3.1.11
fix some minor typos
Fixed critical spinlock when appending empty string
fixed copyright and old version info on schema files
version 3.1.12
add config switch for read-only headername-cache