Add out_of_memory field to mrb_state.
Add the care for malloc failed.
At the first time, mrb_realloc raise RuntimeError.
At the time fails twice in a row, it causes panic.
Fix to fit new raisef format.
Fix typos.
Use mrb_raise() as possible instead of mrb_raisef().
Add fib39.rb to benchmark/
revert 79ebdb5 for the time being #1110
Merge pull request #1123 from monaka/pr-add-fib39-to-benchmark

Add fib39.rb to benchmark/
Merge pull request #1122 from monaka/pr-cleanup-raise

Cleanup around mrb_raise calls
bugfix: Kernel#!=, and add #!= testcase.
Merge pull request #1124 from kouki-o-iij/pr-kernel-notequal

bugfix: Kernel#!=, and add #!= testcase.
Merge pull request #1121 from monaka/pr-check-malloc-failed2

Check malloc failed