ooxml: Preserve shape style effect attributes

Preserve <a:effectRef> tag and its contents from inside shape style
properties tag <wps:style>.

Added some lines to existing unit tests to check for the preservation
of these attributes.

Change-Id: I6e47b228dcc9788a4a2dfe87bd1186d2f04dbeea
ooxml: Small code refactor

* Use PUT_PROPS macro in all cases.
* Added putPropertyToGrabBag( OUString, Any ) to avoid the explicit
  creation of a PropertyValue object every time.

Change-Id: If098dd3a94d1843c4c5dbc3a507b05754d9d59c7