check registered kernel and gemfile
check registered kernel and gemfile

should fix #36 and #31

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