PY-11932 Put nulls for unresolved class types in MRO

Some of the ancestor class-like types may be unresolved. The best we
can do is to put nulls for all the unresolved classes to appropriate
places inside the MRO chain. What we used to do in this case it return
the empty sequence of the ancestors.
Fall back to old-style ancestors if C3 MRO fails and there are unresolved ancestors (PY-11401)

If the C3 MRO algorithm fails and the old-style ancestors algorithm
tells that there are unresolved ancestors, we return a single 'null'
ancestor as a sign that we don't know who the ancestors really are.

If there are no unresolved ancestors, then we fall back to the
old-style ancestors algorithm in order to make resolve work. A future
inspection for detecting incorrect MRO may warn the user about this
situation.
If mro() is overridden in metaclass, use normal MRO + unresolved ancestor (PY-11401)

We cannot evaluate the result of an overridden mro() method, so we
don't know the actual MRO chain. Let's assume that MRO is almost the
same as without this override and add an element of uncertainty by
appending a fake unresolved ancestor type to the MRO chain. Doing so
results in, for example, the unresolved references inspection ignoring
unresolved references for such a class.
don't lowercase tags in html
#WEB-14679 fixed
Merge remote-tracking branch 'origin/master'
IDEA-27486 Make file templates per-project: sharing default scheme
Merge branch 'python-fixes'
Merge remote-tracking branch 'origin/master'
Merge remote-tracking branch 'origin/master'
Merge remote-tracking branch 'origin/master'
OC-11351 Parameter info for Swift
[vcs] IDEA-117448 Fix default PatchReader value
EA-63629 - INRE: FileBasedIndexImpl.handleDumbMode
EA-63628 - INRE: FileBasedIndexImpl.handleDumbMode
make ui form editor non-dumb-aware (EA-63630 - INRE: FileBasedIndexImpl.handleDumbMode)
no getOriginalClass in dumb mode (EA-63632 - INRE: FileBasedIndexImpl.handleDumbMode)
AddModuleDependencyFix: add import only in non-dumb mode (EA-63633 - INRE: FileBasedIndexImpl.handleDumbMode)
allow to create Groovy classes in dumb mode (EA-63626 - INRE: FileBasedIndexImpl.handleDumbMode)
restructure the code a bit to make it clearer and remove unnecessary use of reflection
move PackagesTreeStructureTest to community