imap: Added %{deleted}, %{expunged} and %{trashed} to imap_logout_format

Marked functions parameters that are allowed to be NULL. Some APIs were also changed. The non-obvious APIs where NULL parameter was changed to "" are master_service_init() and auth_master_user_list_init(). These checks can currently be enabled only on a patched clang: http://llvm.org/bugs/show_bug.cgi?id=6786

Make mail_search_args an independent structure that can be used for multiple separate searches. --HG-- branch : HEAD

Fixed CLOSE HIGEHSTMODSEQ race condition. Added some checks to make sure mailbox isn't being closed/opened while the previous SELECT/CLOSE is still being processed. --HG-- branch : HEAD

Changed .h ifdef/defines to use <NAME>_H format. --HG-- branch : HEAD

Added "bool" type and changed all ints that were used as booleans to bool. --HG-- branch : HEAD

mailbox_save() and mailbox_copy() functions can now return the saved mail so it can be immediately queried. Implemented UIDPLUS extension using it. Maildir implementation missing, so it crashes with it for now.. APPEND with mbox now doesn't require resyncing the mailbox since it updates indexes directly. --HG-- branch : HEAD

importing new index code. mbox still broken. --HG-- branch : HEAD

forgot to add --HG-- branch : HEAD