Updated Polish translation
Miscellaneous cleanups.
Update API documentation.
NEWS update for 3.11.91 release.
Post-release version bump.
Remove unused CAMEL_STORE_FOLDER_CREATE_EXCL.

Not used, so not going to bump the libcamel soname over it.
Deprecate CAMEL_STORE_FOLDER_EXCL.

Fortunately Evolution doesn't use this flag, so we can simply remove
code branches that check for it.  I'll remove the flag after 3.12.0.
CamelStore: Handle CAMEL_STORE_FOLDER_CREATE flag directly.

camel_store_get_folder_sync() now handles this flag directly by first
calling get_folder_sync(), and on CAMEL_STORE_ERROR_NO_FOLDER it then
calls create_folder_sync() and retries get_folder_sync().

Subclasses will no longer receive a CAMEL_STORE_FOLDER_CREATE flag,
which should simplify things and yield more consistent behavior.

Solves https://bugzilla.gnome.org/724863, although from a different
angle than the way the problem description is written.
CamelIMAPXServer: Copy child setup gunk from CamelStreamProcess.