[Bug #802] IO.open optional argument to properly handle BOMs

Bug #802: IO.open optional argument to properly handle BOMs
http://redmine.ruby-lang.org/issues/show/802

e$B5/I<<Te(B: Shyouhei U.
e$B%9%F!<%?%9e(B: Open, e$BM%@hEYe(B: Normal
e$BC4Ev<Te(B: Usaku NAKAMURA, e$B%+%F%4%je(B: M17N, Target version:
1.9.x

Rejecte$B$5$l$?e(B[ruby-dev:37075][Feature
#747]e$B$NB3$-$G$9!#5DO@$N7k2Le(BIO.opene$BB&$Ge(BBOMe$B$rE,@Z$K=hM}$9$k$N$,$h$$$@$m$&$H$$$&$3$H$K$J$C$?$h$&$G$9!#e(B

e$B$J$+$`$ie(B(e$B$&e(B)e$B$5$s$N;EMM0F$,e(B[ruby-dev:37081]e$B$K$"$j$^$9!#e(B

e$B%A%1%C%He(B #802 e$B$,99?7$5$l$^$7$?!#e(B (by Usaku NAKAMURA)

e$BC4Ev<Te(B Usaku NAKAMURAe$B$+$ie(BYukihiro M.e$B$KJQ99e(B

e$B;EMM0F$O=P$7$F$"$k$o$1$J$N$Ge(Baccepte$B$+e(Brejecte$B$r7hDj$7$F$/$@$5$$!#e(B

http://redmine.ruby-lang.org/issues/show/802

e$B%A%1%C%He(B #802 e$B$,99?7$5$l$^$7$?!#e(B (by Yui NARUSE)

e$B%9%F!<%?%9e(B Opene$B$+$ie(BClosede$B$KJQ99e(B
e$B?JD=e(B % 0e$B$+$ie(B100e$B$KJQ99e(B

Applied in changeset r24001.

http://redmine.ruby-lang.org/issues/show/802