caldav: gotta not forget to look at FREEBUSY still

Wow, all the crap I wrote that first night is bad :(
caldav: correct ACL handling
read-free-busy correctly
caldav_alarm: always full datetimes for the next alarm time
dav: delayed mailbox delete
dav: add back httpd_authstate to foreach
Revert "dav: add back httpd_authstate to foreach"

This reverts commit 1d8d7add2c5caf3e925ca47abff01828aa836e7f.

Broke ALL prop gets - gotta figure out why, but not right now
annotate: move everything to mask functions, and only shared for owner
http_dav: replace '@' with '%40' in URLs

Ugly, ugly, ugly - but what can you do?  The helper function is bogus.
if you're going to COPY the NULL, you need to make space for the NULL
charset: add alias 'ascii' for 'us-ascii'
message: log invalid charsets for text parts
xapian: don't try to reindex missing folders
windows: 3 extra codepages
charset: more aliases
dav: remove-resource must include EXPUNGE
dav: fixup
xapian: search high-bit phrases without stemming
mboxname: separate counters for different types of mailbox modseq
mailbox: always create a cstring when parsing dav stuff

Otherwise exactly 2^N long messages can segfault, joy