Use mrb_int.
Merge pull request #1936 from ksss/pool-capa

mrb_str_pool add string capa
Use mrb_int instead of int
REnv uses obj->c as env link; no super
Merge branch 'master' of github.com:mruby/mruby
Merge pull request #1937 from cubicdaiya/issues/mrb_int

Use mrb_int instead of int
use to_int to integer duck-type check
Use mrb_int instead of int
Enumerable#find_index
Merge pull request #1938 from cubicdaiya/issues/suitable_type2

Use mrb_int instead of int
Merge pull request #1939 from suzukaze/add-enum.find_index

Enumerable#find_index
Enumerable#find_index to support multiple values
Use mrb_int instead of int
Fix unnecessary string macro
Merge pull request #1945 from cubicdaiya/issues/suitable_type3

Use mrb_int instead of int
Merge pull request #1946 from ksss/str-macro

Fix unnecessary string macro
add new function mrb_toplevel_run to prevent running through C function boudaries on exceptions; close #1942
Merge branch 'master' of github.com:mruby/mruby
Remove redundant NULL checks.
mrb_malloc causes an exception when memory was empty.
Add tests for mruby-eval.