Allow tilde expansion for htpasswd file

Call os.path.expanduser on the location given by the config parameter.
This will allow to use settings like
  htpasswd_filename = ~/.config/radicale/users
Fix #143

Since all iCalendar objects have VCALENDAR inside them, that tag is
absolutely meaningless (in this context).
Merge pull request #169 from untitaker/issue143

Fix #143
Merge pull request #160 from red-hood/master

Allow tilde expansion for htpasswd file
Use warning instead of warn for logging (fix #170)
Signed-off-by: Ede123 <Eduard.Braun2@gmx.de>
Sort items before serializing to minimize diff
revert of 00674fe
deplace pid file creation in child process
Merge pull request #190 from deronnax/pid_file_creation_in_child

deplace pid file creation in child process
else if → elif
Merge pull request #189 from deronnax/revert#00674fe

revert of 00674fe
Merge pull request #175 from Ede123/master

Return "401 unauthorized" on unauthorized DELETE requests (fixes #125)
Merge pull request #182 from dnnr/serialize-sorted

Sort items before serializing to minimize diff
Fix syntax error