・Slightly modified the wording in the paragraph immediately
　following Corollary B

・Added some supplementary explanatory paragraphs following
　Corollary C

・Added Remark 3.12.2, as well as a reference to this remark
　immediately preceding Theorem D

・Added a reference to [CmbCusp], Remark 4.2.1, at the end of
　Definition 2.7

・Modified slightly misleading wording in the statement of
　Corollary 2.10, (iv)

・Added [AbsTopIII], [Pano] to the list of references