fix regexp warning: character class has duplicated range
remove unused variables
Merge pull request #1244 from NARKOZ/regexp-warning

fix regexp warning: character class has duplicated range
Print mrb_value instead of RClass*
Merge pull request #1247 from carsonmcdonald/issue1246fix

Print mrb_value instead of RClass*
Merge pull request #1245 from NARKOZ/fix-warnings

remove unused variables