Windows compatibility
Windows compatibility

Almost same as I did in v0.2.7
(fda30d610786db4e2929554de37ba25972846f36)

SciRuby/iruby,zalt50/iruby,zalt50/iruby,SciRuby/iruby,SciRuby/iruby,zalt50/iruby,zalt50/iruby,SciRuby/iruby