PPTX: inheritance Kung Fu

* DEFAULTS: Only a common shape (not a placeholder) starts the inheritance
sequence from defaults defined in the presentation.xml file. That kind of
shape does not provide a reference to a placeholder or a style in the ph
element (Placeholder Shape - ECMA-376 Part 1, 19.3.1.36 ).

List Styles:
------------

* DO NOT overwrite the primary styles defined in a MasterSlide while reading
the placeholder shapes therein or in the SlideLayout. Save the corresponding
modification under the placeholder-ID. The only allowed case is a shape with
the ph element having ONLY the type attribute. That kind of a placeholder
modifies the primary style. Of course if a placeholder with a type attribute
not already in the map is found in the MasterSlide, then save it.

* When inheritance goes on, DO check if the map contains the nested map of
levels and corresponding ParagraphBulletProperties, else the constructor gets
called and you will get EMPTY ParagraphBulletProperties full of "UNUSED"
values.

* When inheritance goes on, DO NOT overwrite the already inherited
currentBulletProperties by "UNUSED" values when you find an EMPTY
ParagraphBulletProperties entry. Only valid values therein have to be
inherited. In means of ParagraphBulletProperties, EMPTY means it's not
directly related to a specific list-level-style-{number/bullet/picture}.
However it might define margin-*, text-indent, padding-*, etc.

* Do not inherit from already processed shapes on the same presentation slide.
Is there any use case for this? Also disabled that kind of inheritance for
Notes.

Placeholder Position:
---------------------

* DO NOT overwrite the primary styles defined in a MasterSlide while reading
the placeholder shapes therein or in the SlideLayout. Save the corresponding
modification under the placeholder-ID. The only allowed case is a shape with
the ph element having ONLY the type attribute. That kind of a placeholder
modifies the primary style. Of course if a placeholder with a type attribute
not already in the map is found in the MasterSlide, then save it.

* When inheritance goes on, DO check if the shapes map contains the key to the
corresponding PptxShapeProperties.

Text Styles:
----------------------

* Changed the inheritance order, first inherit by type and then by ID like at
other places. The different order was probably some workaround.

* DO NOT overwrite the primary styles defined in a MasterSlide while reading
the placeholder shapes therein or in the SlideLayout. Save the corresponding
modification under the placeholder-ID. The only allowed case is a shape with
the ph element having ONLY the type attribute. That kind of a placeholder
modifies the primary style. Of course if a placeholder with a type attribute
not already in the map is found in the MasterSlide, then save it.

* When inheritance goes on, DO check if the map contains the key to the nested
map of levels and the corresponding KoGenStyle. Also check if the nested map
contains the key to the KoGenStyle.

* Do not inherit from already processed shapes on the same presentation slide.
Is there any use case for this? Also disabled that kind of inheritance for
Notes.

* It seems that IF processing SlideLayout shapes of type="Body", THEN the
formatting of the corresponding placeholder of the MasterSlide has to be
reset first, because the SlideLayout defines a new placeholder of type="Body"
(new ID or redefines the MasterSlide placeholder with the ID).

* It seems that IF some of the properties for text chunks are not provided for
the specific type of text, THEN we should inherit from type="Other". Testing
with font-size at the moment.

TESTING:

* It seems that IF some of the properties are missing for "title" or "body"
text, THEN inherit from "other" text (instead of the defaults of course).

* Text of type "subTitle" should inherit from "body" instead of "other".
Doesn't work with "title" of course.

Paragraph Styles:
----------------------
TODO, The logic differs a bit from text styles.

NOTE: Took a lot of cstester runs. Reused a lot of the ppt filter logic.