Add tests for Range#to_s Range#inspect.
Add Hash#key
OP_ENTER clean block object in register
Add ISO No. to String#inspect test.
Merge pull request #2212 from yui-knk/add-range-test

Add tests for Range#to_s Range#inspect.
Merge pull request #2213 from suzukaze/add-hash.key

Add Hash#key
Merge pull request #2215 from yui-knk/fix-typo-test

Add ISO No. to String#inspect test.
Merge pull request #2214 from ksss/proc-clear

OP_ENTER clean block object in register
libreadline requires libtermcap on OpenBSD.
Merge pull request #2216 from iij/pr-mirb-link-termcap

libreadline requires libtermcap on OpenBSD.