src/string.c RESIZE_CAPA use safe name variables
This has a possibility of naming conflicts
Fix Enumerable#cycle; ref #1933

* add multi value support
* `each` method may not rewind the sequence so that `cycle` should save elements
Merge pull request #1934 from ksss/safe-name

src/string.c RESIZE_CAPA use safe name variables
Implement ObjectSpace.each_object .
mrb_str_pool add string capa
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