Merge branch 'suppress_intern' of https://github.com/crimsonwoods/mruby into crimsonwoods-suppress_intern

Clean up load.c

Fix-up string

Add error checks for small environments which pointer is less than 32bit. These code will be removed by optimizer if the target runs on 32bit or above.

fix the behavior of Module#ancestors

String#inspec & String#dump may raise an "arena overflow" error

Set ENV before loading Rakefile in minirake

Fix segfault on loading binary RITE files.

Fix wrong comment

fix unnecessary irep_free on load.c

Pass verbose flag to each gem test