VPopMail 5.6.1

• vmysql.c: allow the insertion of a second valias row with the same alias/domain
  when vpopmail is configured with --enable-defaultdelivery and --enable-valias
• bug fix in mysql.h: wrong definition of VALIAS_TABLE_LAYOUT as it was looking
  for DEFAULTDELIVERY definition instead of DEFAULT_DELIVERY
• configure.ac: solved all autoconf warnings

VPopMail 5.6.0

Adds new features and fixes bugs.
Merge patches from different sources, see ChangeLog for more details.