tests corrected for new schema
DOM: use null, not empty StringRef for non-set ElementStub#elementClass
Merge remote-tracking branch 'origin/master'
[log] refactor: group filters before passing them to providers

Instead of passing a Collection of VcsLogFilter and thus forcing each
VcsLogProvider sort filters by type on its own,
group them in the common code and pass a separate Collection of each
filter type.

Extract interfaces for each filter type to let them be used in
VcsLogProvider.
[log] IDEA-116322 Fix structure filter for multiple roots

Pass only those structure filters to the VcsLogProvider which match
files from the given root.

If there is a structure filter, but it doesn't match some root
(doesn't have files/folder belonging to this root),
the log provider shouldn't be asked about this root at all.
IDEA-117373 Spacing options for Java type arguments/parameters [CR-IC-4071]
Fixed NPE