・Corrected a misprint in Remark 1.2.3 ("Definition 2.1" ---> "Definition 1.2")

・Added a supplementary explanation at the end of Remark 1.2.3

・Corrected a misprint in Proposition 1.3, (vi) ("an vertex" ---> "a vertex")

・Added a supplementary explanation at the end of Remark 1.5.3

・Corrected a mistake in the definition of "strict" in Definition 1.9, (iii)

・Corrected slight misstatements in Corollaries 1.10, 1.11 concerning the hypothesis involving
　"strictness"

・Corrected a slight misstatement in the definition of the "exceptional divisor" in
　Definition 2.4, (ii)

・Corrected an error in the statement of the final portion of Proposition 2.5, (iii),
　and its proof (concerning the term "tamely ramified") that arose in the modifications 
　made in April 2013 by restoring the text of the version of the paper that existed prior 
　to these modifications 

・Corrected a misprint ("Strictly" ---> "Strict") in Corollary 1.11, (ii)

・Modified the final portion of Definition 2.4, (ii) (added the notion of being "unramified at C")

・Corrected an error in the statement and proof of the final portion of Proposition 2.5, (iv)

・Modified the proof of Proposition 2.5, (v), to take into account the corrections to Proposition 
　2.5, (iv)

・Slightly modified the conditions placed on V'', V' in the proof of Lemma 2.6, (ii) (added the 
　condition "unramified", which is then quoted in the subsequent application of Proposition 2.5, (iv), 
　to the computation of logarithmic differentials)